Gonadotrophin‐releasing hormone antagonists for assisted reproductive technology

Hesham G Al‐Inany; Mohamed A Youssef; Reuben Olugbenga Ayeleke; Julie Brown; Wai Sun Lam; Frank J Broekmans

doi:10.1002/14651858.CD001750.pub4

. 2016 Apr 29;2016(4):CD001750. doi: 10.1002/14651858.CD001750.pub4

Gonadotrophin‐releasing hormone antagonists for assisted reproductive technology

Hesham G Al‐Inany ^1,^✉, Mohamed A Youssef ¹, Reuben Olugbenga Ayeleke ², Julie Brown ³, Wai Sun Lam ², Frank J Broekmans ⁴

Editor: Cochrane Gynaecology and Fertility Group

PMCID: PMC8626739 PMID: 27126581

Abstract

Background

Gonadotrophin‐releasing hormone (GnRH) antagonists can be used to prevent a luteinizing hormone (LH) surge during controlled ovarian hyperstimulation (COH) without the hypo‐oestrogenic side‐effects, flare‐up, or long down‐regulation period associated with agonists. The antagonists directly and rapidly inhibit gonadotrophin release within several hours through competitive binding to pituitary GnRH receptors. This property allows their use at any time during the follicular phase. Several different regimens have been described including multiple‐dose fixed (0.25 mg daily from day six to seven of stimulation), multiple‐dose flexible (0.25 mg daily when leading follicle is 14 to 15 mm), and single‐dose (single administration of 3 mg on day 7 to 8 of stimulation) protocols, with or without the addition of an oral contraceptive pill. Further, women receiving antagonists have been shown to have a lower incidence of ovarian hyperstimulation syndrome (OHSS). Assuming comparable clinical outcomes for the antagonist and agonist protocols, these benefits would justify a change from the standard long agonist protocol to antagonist regimens. This is an update of a Cochrane review first published in 2001, and previously updated in 2006 and 2011.

Objectives

To evaluate the effectiveness and safety of gonadotrophin‐releasing hormone (GnRH) antagonists compared with the standard long protocol of GnRH agonists for controlled ovarian hyperstimulation in assisted conception cycles.

Search methods

We searched the Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched from inception to May 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, inception to 28 April 2015), Ovid MEDLINE (1966 to 28 April 2015), EMBASE (1980 to 28 April 2015), PsycINFO (1806 to 28 April 2015), CINAHL (to 28 April 2015) and trial registers to 28 April 2015, and handsearched bibliographies of relevant publications and reviews, and abstracts of major scientific meetings, for example the European Society of Human Reproduction and Embryology (ESHRE) and American Society for Reproductive Medicine (ASRM). We contacted the authors of eligible studies for missing or unpublished data. The evidence is current to 28 April 2015.

Selection criteria

Two review authors independently screened the relevant citations for randomised controlled trials (RCTs) comparing different GnRH agonist versus GnRH antagonist protocols in women undergoing in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI).

Data collection and analysis

Two review authors independently assessed trial eligibility and risk of bias, and extracted the data. The primary review outcomes were live birth and ovarian hyperstimulation syndrome (OHSS). Other adverse effects (miscarriage and cycle cancellation) were secondary outcomes. We combined data to calculate pooled odds ratios (ORs) and 95% confidence intervals (CIs). Statistical heterogeneity was assessed using the I² statistic. We assessed the overall quality of the evidence for each comparison using GRADE methods.

Main results

We included 73 RCTs, with 12,212 participants, comparing GnRH antagonist to long‐course GnRH agonist protocols. The quality of the evidence was moderate: limitations were poor reporting of study methods.

Live birth

There was no evidence of a difference in live birth rate between GnRH antagonist and long course GnRH agonist (OR 1.02, 95% CI 0.85 to 1.23; 12 RCTs, n = 2303, I²= 27%, moderate quality evidence). The evidence suggested that if the chance of live birth following GnRH agonist is assumed to be 29%, the chance following GnRH antagonist would be between 25% and 33%.

OHSS

GnRH antagonist was associated with lower incidence of any grade of OHSS than GnRH agonist (OR 0.61, 95% C 0.51 to 0.72; 36 RCTs, n = 7944, I² = 31%, moderate quality evidence). The evidence suggested that if the risk of OHSS following GnRH agonist is assumed to be 11%, the risk following GnRH antagonist would be between 6% and 9%.

Other adverse effects

There was no evidence of a difference in miscarriage rate per woman randomised between GnRH antagonist group and GnRH agonist group (OR 1.03, 95% CI 0.82 to 1.29; 34 RCTs, n = 7082, I² = 0%, moderate quality evidence).

With respect to cycle cancellation, GnRH antagonist was associated with a lower incidence of cycle cancellation due to high risk of OHSS (OR 0.47, 95% CI 0.32 to 0.69; 19 RCTs, n = 4256, I² = 0%). However cycle cancellation due to poor ovarian response was higher in women who received GnRH antagonist than those who were treated with GnRH agonist (OR 1.32, 95% CI 1.06 to 1.65; 25 RCTs, n = 5230, I² = 68%; moderate quality evidence).

Authors' conclusions

There is moderate quality evidence that the use of GnRH antagonist compared with long‐course GnRH agonist protocols is associated with a substantial reduction in OHSS without reducing the likelihood of achieving live birth.

Keywords: Adult; Female; Humans; Reproductive Techniques, Assisted; Gonadotropin‐Releasing Hormone; Gonadotropin‐Releasing Hormone/agonists; Gonadotropin‐Releasing Hormone/antagonists & inhibitors; Live Birth; Ovarian Hyperstimulation Syndrome; Ovarian Hyperstimulation Syndrome/prevention & control; Ovulation Induction; Ovulation Induction/methods; Randomized Controlled Trials as Topic

Plain language summary

Gonadotrophin‐releasing hormone antagonists versus GnRH agonist in subfertile couples undergoing assisted reproductive technology

Review question

This updated Cochrane review evaluated the efficacy and safety of GnRH antagonists compared to the more widely‐used GnRH agonists (long‐course protocol).

Background:

Gonadotrophin‐releasing hormone (GnRH) agonist is commonly used to prevent cycle cancellation secondary to a premature luteinizing hormone (LH) surge, and thereby increase the chance of live birth in women undergoing assisted reproductive technology (ART), while reducing the risk of complications such as ovarian hyperstimulation syndrome (OHSS). Gonadotrophin‐releasing hormone (GnRH) antagonists are now being seriously considered as a potential means of achieving better treatment outcomes because the protocol is more flexible and antagonists may reduce OHSS more effectively than agonists. However, there is the need to evaluate the benefits as well as the safety of these GnRH antagonist regimens in comparison with the existing GnRH agonist regimens.

Study characteristics

We found 73 randomised controlled trials comparing GnRH antagonist with GnRH agonist in a total of 12,212 women undergoing ART. The evidence is current to May 2015

Key results

There was no evidence of a difference between the groups in live birth rates (i.e. rates at conclusion of a course of treatment). The evidence suggested that if the chance of live birth following GnRH agonist is assumed to be 29%, the chance following GnRH antagonist would be between 25% and 33%. However, the OHSS rates were much higher after GnRH agonist. The evidence suggested that if the risk of OHSS following GnRH agonist is assumed to be 11%, the risk following GnRH antagonist would be between 6% and 9%.

Quality of the evidence

The evidence was of moderate quality for both live birth and OHSS. The main limitations of the evidence were the possibility of publication bias for live birth (with small studies likely to report favourable outcomes for GnRH antagonist) and poor reporting of study methods for OHSS.

Summary of findings

Summary of findings for the main comparison. GnRH antagonist compared to long‐course GnRH agonist for assisted reproductive technology (ART).

GnRH antagonist compared to long‐course GnRH agonist for assisted reproductive technology (ART)
Population: women undergoing assisted reproductive technology (ART)  Settings: clinic for ART  Intervention: GnRH antagonist  Comparison: long‐course GnRH agonist
Outcomes	*Illustrative comparative risks (95% CI)**		Relative effect  (95% CI)	No of Participants  (studies)	Quality of the evidence  (GRADE)	Comments
	Assumed risk	Corresponding risk
	Long course GnRH agonist	GnRH antagonist
Live birth rate per woman randomised	286 per 1000	290 per 1000   (254 to 330)	OR 1.02   (0.85 to 1.23)	2303  (12 studies)	⊕⊕⊕⊝  moderate¹
OHSS per woman randomised (any grade)	114 per 1000	73 per 1000   (62 to 85)	OR 0.61   (0.51 to 0.72)	7944  (36 studies)	⊕⊕⊕⊝  moderate²
Ongoing pregnancy rate per woman randomised	293 per 1000	276 per 1000   (256 to 295)	OR 0.92   (0.83 to 1.01)	8311  (37 studies)	⊕⊕⊕⊝  moderate²
Clinical pregnancy rate per woman randomised	303 per 1000	283 per 1000   (267 to 303)	OR 0.91   (0.83 to 1)	9959  (54 studies)	⊕⊕⊕⊝  moderate²
Miscarriage rate per woman randomised	48 per 1000	49 per 1000   (40 to 61)	OR 1.03   (0.82 to 1.29)	7082  (34 studies)	⊕⊕⊕⊝  moderate²
Cycle cancellation due to poor ovarian response	64 per 1000	83 per 1000   (68 to 101)	OR 1.32   (1.06 to 1.65)	5230  (25 studies)	⊕⊝⊝⊝  moderate^3,4
The basis for the assumed risk* (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).  CI: Confidence interval; OR: Odds ratio;
GRADE Working Group grades of evidence  High quality: Further research is very unlikely to change our confidence in the estimate of effect.  Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.  Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.  Very low quality: We are very uncertain about the estimate.

Date	Event	Description
9 May 2016	Amended	Correction to reinstate data removed in error (Marci 2005)
3 February 2016	New citation required and conclusions have changed	The addition of new studies did not change the conclusions of this review.
3 February 2016	New search has been performed	This review has been updated, and 28 new studies added.
7 July 2011	Amended	Minor amendments to new citation version published May 2011
13 April 2011	New search has been performed	Authorship: new author added (Mohamed AFM Youssef) and order of authors changed 27 new studies were added New comparisons: cetrorelix versus ganirelix New subgroups: poor responders; PCOS; GnRH antagonist plus OCP; flexible antagonist protocol; fixed antagonist protocol; mild IVF A date limited search of Cochrane Menstrual Disorders and Subfertility Group Specialised Register, CENTRAL from April 2010 to April 2011 was run. 18 studies have been entered into the Classification pending references section of this update. These studies will be appraised for inclusion or exclusion in the next update of this review, due April 2012.
13 April 2011	New citation required and conclusions have changed	The conclusion has changed
13 June 2008	Amended	Converted to new review format.
19 May 2006	New citation required and conclusions have changed	Substantive amendment

#	Query	Results
S34	S21 AND S33	56
S33	S22 OR S23 OR S24 OR S25 OR S26 OR S27 OR S28 OR S29 OR S30 OR S31 OR S32	956,465
S32	TX allocat* random*	4,252
S31	(MH "Quantitative Studies")	13,346
S30	(MH "Placebos")	9,191
S29	TX placebo*	33,691
S28	TX random* allocat*	4,252
S27	(MH "Random Assignment")	39,039
S26	TX randomi* control* trial*	86,342
S25	TX ( (singl* n1 blind) or (singl n1 mask) ) or TX ( (doubl n1 blind) or (doubl n1 mask) ) or TX ( (tripl n1 blind) or (tripl n1 mask) ) or TX ( (trebl n1 blind) or (trebl n1 mask*) )	765,037
S24	TX clinic* n1 trial*	171,259
S23	PT Clinical trial	77,774
S22	(MH "Clinical Trials+")	186,608
S21	S9 AND S20	92
S20	S10 OR S11 OR S12 OR S13 OR S14 OR S15 OR S16 OR S17 OR S18 OR S19	805
S19	(MM "Goserelin")	93
S18	(MM "Leuprolide")	124
S17	TX (GNRH‐a or GNRH a)	129
S16	TX (decapeptyl or trelstar)	8
S15	TX triptorelin or TX Zoladex	61
S14	TX (leuprolide or nafarelin)	286
S13	TX (buserelin or goserelin)	246
S12	TX GnRH agonist*	160
S11	TX gonadotrophin releasing hormone agonist*	37
S10	TX gonadotropin releasing hormone agonist*	190
S9	S1 OR S2 OR S3 OR S4 OR S5 OR S6 OR S7 OR S8	159
S8	TX Degarelix	35
S7	TX Antagon	2
S6	TX (Abarelix or Plenaxis)	8
S5	TX Ganirelix	13
S4	TX (Cetrorelix or Cetrotide)	14
S3	TX GnRH antagonist*	86
S2	TX gonadotrophin releasing hormone antagonist*	16
S1	TX gonadotropin releasing hormone antagonist*	47

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Live birth rate per woman randomised	12	2303	Odds Ratio (M‐H, Fixed, 95% CI)	1.02 [0.85, 1.23]
2 Live birth rate per woman randomised ‐ minimal stimulation	2	524	Odds Ratio (M‐H, Fixed, 95% CI)	0.89 [0.62, 1.26]
3 Live birth rate per woman randomised ‐ grouped by trigger	12	2303	Odds Ratio (M‐H, Fixed, 95% CI)	1.02 [0.85, 1.23]
3.1 hCG trigger	11	1899	Odds Ratio (M‐H, Fixed, 95% CI)	1.09 [0.89, 1.34]
3.2 Unknown trigger	1	404	Odds Ratio (M‐H, Fixed, 95% CI)	0.80 [0.54, 1.21]
4 Ovarian hyperstimulation per woman randomised ‐ all women	36	7944	Odds Ratio (M‐H, Fixed, 95% CI)	0.61 [0.51, 0.72]
5 Ovarian hyperstimulation per woman randomised ‐ moderate or severe	20	5141	Odds Ratio (M‐H, Fixed, 95% CI)	0.53 [0.40, 0.69]
6 Ongoing pregnancy rate per woman randomised ‐ all women	37	8311	Odds Ratio (M‐H, Fixed, 95% CI)	0.92 [0.83, 1.01]
7 Ongoing pregnancy rate per woman randomised ‐ minimal stimulation	7	1456	Odds Ratio (M‐H, Fixed, 95% CI)	0.94 [0.75, 1.18]
8 Ongoing pregnancy rate per women randomised ‐ grouped by trigger	37		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
8.1 hCG trigger	29	5170	Odds Ratio (M‐H, Fixed, 95% CI)	0.95 [0.84, 1.08]
8.2 Mixed trigger (hCG/GnRH agonist)	1	66	Odds Ratio (M‐H, Fixed, 95% CI)	0.61 [0.23, 1.61]
8.3 Unknown trigger	7	3075	Odds Ratio (M‐H, Fixed, 95% CI)	0.87 [0.74, 1.03]
9 Clinical pregnancy rate per woman randomised ‐ all women	54	9959	Odds Ratio (M‐H, Fixed, 95% CI)	0.91 [0.83, 1.00]
10 Clinical pregnancy rate per woman randomised ‐ minimal stimulation	6	1102	Odds Ratio (M‐H, Fixed, 95% CI)	1.50 [1.15, 1.96]
11 Miscarriage rate per woman randomised	34	7082	Odds Ratio (M‐H, Fixed, 95% CI)	1.03 [0.82, 1.29]
12 Miscarriage rate per clinical pregnancy	34	2308	Odds Ratio (M‐H, Fixed, 95% CI)	1.08 [0.84, 1.37]
13 Cycle cancellation rate per woman randomised	34		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
13.1 Cancellation due to high risk of OHSS	19	4256	Odds Ratio (M‐H, Fixed, 95% CI)	0.47 [0.32, 0.69]
13.2 Cancellation due to poor ovarian response	25	5230	Odds Ratio (M‐H, Fixed, 95% CI)	1.32 [1.06, 1.65]

Methods	RCT, parallel design
Participants	124 poor responders undergoing IVF
Interventions	GnRH antagonist (n = 62): 450 IU HP‐FSH (Urofollitropin) + cetrorelix 0.25 mg daily added to the ovarian stimulation when the largest follicle measures ≥ 14 mm (flexible protocol) GnRH agonist (n = 62): 450 IU HP‐FSH (Urofollitropin) + triptoreline 0.05 mg daily (half the standard dose) initiated in the mid‐luteal phase prior to the treatment cycle (minidose long protocol) Mean number of embryos transferred: antagonist: 2.1 ± 1.2 versus agonist: 2.3 ± 1.3 Follow‐up: Up to clinical pregnancy
Outcomes	Clinical pregnancy rate, cycle cancellation rate, duration of stimulation, total gonadotrophins requirement, estradiol level on day of hCG, mean numbers of mature oocytes retrieved, mean numbers of embryos formed, mean numbers of embryos transferred
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of random sequence generation not reported
Allocation concealment (selection bias)	Unclear risk	Method of allocation not reported
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Blinding not reported but unlikely to influence measurement of outcomes
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	Insufficient data provided regarding withdrawals
Selective reporting (reporting bias)	Unclear risk	Study protocol not available to identify outcomes of interest. Live birth rate not reported
Other bias	Low risk	None identified

Methods	RCT, open‐label parallel design, multi‐centre (7 centres), multi‐national
Participants	293 Infertile couples undergoing ovarian stimulation for IVF‐ET with or without ICSI Inclusion criteria: with no more than three previous IVF‐ET attempts with all causes of infertility (except polycystic ovary and moderate or severe endometriosis) Baseline characteristics: age 31.9 ± 3.7 versus 31.6 ± 3.8. Duration of infertility: not stated. FSH: not stated. BMI not stated
Interventions	Group I (n = 198): hMG (menogon, humegon, pergonal) was started at 2 or 3 ampoules for four days and the dose was adjusted according to response + multiple‐dose regimen of 0.25 mg of GnRH antagonist (cetrorelix) was administered SC starting from day 6 of hMG treatment to 115 participants up to and including day of hCG administration (Fixed) Group II, GnRH agonist (n = 95): mid‐luteal GnRH analogue (Buserlin 150 µg four times daily intranasally) + hMG (menogon, humegon,pergonal) was started at 2 or 3 ampoules for four days and the dose was adjusted according to response Luteal phase support: daily vaginal progesterone or hCG injections
Outcomes	Premature LH surge defined as (LH > 10 IU/L) and progesterone level > 1 ng/L. Stimulation length, no. of hMG ampoules. E2 on hCG, no of oocytes retrieved, clinical pregnancy/OPU, clinical pregnancy/ET. Miscarriage  Ectopic. Moderate or severe OHSS. Clinical pregnancy was defined as fetal heart beat on ultrasonography. Ongoing pregnancy was defined as pregnancy ongoing after 12 weeks of amenorrhoea
Notes	Number of ICSI cases was not stated in the cetrorelix group or in the buserelin group. Implantation rate was not mentioned as an outcome variable also, no of embryos obtained and no of embryos transferred was not stated. Incidence of multiple pregnancies was not mentioned in the table of outcomes and was not clear in the text. Tolerability was not mentioned Centre‐adjusted analysis was done for all outcomes except miscarriage, ectopic and ovarian hyperstimulation syndrome
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Only reported as a randomised trial with no further details of how randomisation was performed
Allocation concealment (selection bias)	Low risk	Concealed; central telephone, 2:1 randomisation ratio
Blinding (performance bias and detection bias)   All outcomes	High risk	Open
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports include most expected outcomes
Other bias	Unclear risk	Supported by pharmaceutical company, the study appears to be free from other sources of bias

Methods	RCT
Participants	41 women Inclusion criteria: 21 to 40 years, anti‐Mullerian hormone > 1 ng/ml Exclusion criteria: no details Setting and timing: no details of setting. USA. No details of timing Baseline characteristics: no details
Interventions	GnRH antagonist (no details) (n = 21) when follicle size reached 12 mm during the COS cycle Agonist (Leuprolide acetate) (n = 20) starting on day 18 of the oral contraceptive pill cycle Fixed protocol of human derived gonadotrophins at a 3:1 ratio (225/75 IU) for the first four days of stimulation followed by a flexible protocol to improve response hCG given when at least three follicles reached 17 mm diameter All women underwent a cycle using an oral contraceptive pill before starting the controlled ovarian stimulation cycle for IVF
Outcomes	E2, LH, oocytes retrieved, mature oocytes, fertilisation rate, implantation rate, pregnancy rate
Notes	The table included in the abstract does not match the abstract. No data could be included in the meta‐analyses Sample size calculation ‐ unclear ITT analysis ‐ unclear Funding ‐ Ferring Pharmaceuticals
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	'randomised' no other details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	No details, unlikely to be blinded but this should not influence fertility outcomes
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	Conference abstract, unclear if this is the full sample size or reporting preliminary data
Selective reporting (reporting bias)	High risk	No raw data reported. The table does not match the abstract. No full paper identified
Other bias	Unclear risk	Conference abstract only. No details of demographics

Methods	RCT
Participants	413 women (564 cycles) Inclusion criteria: women < 40 years undergoing COH but no other details Exclusion criteria: not stated Baseline characteristics: not stated Setting and timing: no details
Interventions	Agonist long protocol ‐ no details Agonist short protocol ‐ no details Antagonist protocol ‐ no details
Outcomes	Pregnancy rate, miscarriage rate
Notes	Data are only reported as the number of antral follicles and not by the allocated treatment. The denominator for the pregnancy rate does not match either the total number of women or the number of cycles. Data could not be included in a meta‐analysis
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	‘randomly received’ no other details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	No details
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	No details
Selective reporting (reporting bias)	High risk	Conference abstract only. No details as to number allocated to each group. Pregnancy and miscarriage rates reported only
Other bias	Unclear risk	Conference abstract only

Methods	RCT, two‐centre trial
Participants	111 infertile women undergoing IVF/ICSI Inclusion criteria: were not at an a priori increased risk for chromosomally abnormal embryos. < 38 years of age, regular indication for IVF and with a partner with a sperm count > 5 million progressively motile sperm per millilitre, regular menstrual cycles (ranging from 25 to 35 days), BMI 19 ‐ 29 kg m², no  known chromosomal abnormalities, no relevant systemic disease or uterine and ovarian abnormalities, no history of recurrent miscarriage, and no previous IVF cycles not resulting in an embryo transfer Baseline characteristics:female age (years) 34.1 (28 – 37) vs 33.2 (22 – 37), basal FSH 8.1 (4.4 – 13.8) vs 7.6 (5.5 – 18.4), Inhibin B level on cycle day 3 or 4: 86 (2 – 1056) vs 88 (15 – 593)
Interventions	Group I (n = 67):150 IU FSH on 2nd day of the cycles (fixed) + 0.25 mg SC of GnRH antagonist co‐treatment (ganirelix (Orgalutran)) administered when at least one follicle measuring > 14 mm (flexible protocol) GnRH agonist (n = 44): 225 IU rFSH (fixed) + long GnRH agonist, 0.1 mg triptorelin(Long GnRH agonist protocol) Oocyte maturation triggering: 10,000 IU SC hCG (Pregnyl) when one follicle > 18 mm plus 2 follicles > 15 mm  Oocyte retrieval: 35 hours later, followed by IVF/ICSI. Maximum embryos transferred: 2 Follow up: OPR was confirmed by vaginal ultrasound scan at 12 weeks of gestation
Outcomes	Primary outcome measures: ovarian response, as assessed by the number of oocytes obtained and the proportion of chromosomally abnormal embryos per participant. This was expressed as the ratio of abnormal embryos on the number of embryos diagnosed per participant.  Secondary outcome measures: proportion of fertilised oocytes, the proportion of embryos with normal morphology and the proportion of embryos biopsied and diagnosed
Notes	Drop out: 27 out of 67 (40%) women were either lost before oocyte retrieval, fertilisation or embryo biopsy in mild group. 11 out of 44 (25%) women did not reach PGS analysis after conventional stimulation The study was terminated prematurely, after an unplanned interim analysis (which included 61% of the planned number of women) found a lower embryo aneuploidy rate following mild stimulation
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation schedule in a ratio of 4:6 (conventional group: mild group)
Allocation concealment (selection bias)	Low risk	Numbered sealed envelopes. After the participant agreed to participate, the next available numbered envelope on entry into the study was opened by the treating physician during the preparatory IVF consultation
Blinding (performance bias and detection bias)   All outcomes	Low risk	Embryologist
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	High risk	Funding was provided by university and non‐governmental organisation Early stopping due to benefit occurred. "The proportion of chromosomally abnormal embryos per patient was found to be significantly reduced after mild ovarian stimulation (P ¼ 0.02, which is below the Pocock critical bound of 0.0354 for a single interim analysis after 61% (111 of 181) of women had been included (Pocock, 1977)) and the study was terminated."

Methods	RCT, single‐centre, open‐label, parallel design
Participants	100 infertile women undergoing ICSI Inclusion criteria: primary infertility patients, 18 to 39 years old, with regular menstrual cycle and FSH levels < 10 IU/L done at cycle day 3 and ultrasound examination showed normal uterus Exclusion criteria:women with severe endometriosis (American Fertility Society stage III and IV), and azoospermic males were excluded from the study Baseline characteristics: age 30.8 ± 4.8 vs 30.28 ± 5.9 years
Interventions	GnRH antagonist (n = 50): 225 IU Menogon hMG (menogon, humegon, pergonal) was started at 2 or 3 ampoules for four days (adjusted) + 0.25 mg of GnRH antagonist SC ganirelix started from day 6 of hMG treatment/lead follicle measures 14 mm (Flexible multiple‐dose GnRH antagonist)   GnRH agonist (n = 50): mid‐luteal GnRH analogue, buserelin 150 ug four times daily intranasally (Suprefact) + 225 IU hMG (menogon, humegon, pergonal) was started at 2 or 3 ampoules for four days and the dose was adjusted according to response (Long GnRH agonist) Oocyte maturation triggering: hCG 10,000 IU (Choriomon) was administered deeply IM when the leading follicle reached 20 mm in mean diameter with at least three follicles > 18 mm Oocyte retrieval: 34 ‐ 36 hours Embryo transfer: 2 ‐ 3 days after OPU  Luteal phase support: Cyclogest (Shire Pharmaceuticals Ltd., Andover, UK) vaginal pessaries, 400 mg twice a day continued for two weeks. B‐hCG was done two weeks following embryo transfer and if negative Cyclogest was stopped. If, however, pregnancy test (B‐hCG) was positive, Cyclogyst was continued until 12 weeks' gestation
Outcomes	Female partner age Infertility duration years Baseline FSH mIU/ml Day 3 LH mIU/ml Day 14 E2 pg/ml E2 pg/ml on day of hCG hMG ampoule Stimulation duration Number of follicles Size of follicles (mm) Endometrial thickness Number of oocytes retrieved Number of MII oocytes Number of oocytes fertilised Fertilisation rate Embryos No of transferred embryos Pregnancy rate/ET Abortion rate OHSS
Notes	Number of participants at randomisation: 100 (ganirelix 50/Superfact 50)  Number of participants at stimulation: 100 (ganirelix 50/Superfact 50)  Number of participants at OPU: 95 (ganirelix 47/Superfact 50)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation stated to be using sealed envelopes without any further details
Allocation concealment (selection bias)	Low risk	Sealed envelopes
Blinding (performance bias and detection bias)   All outcomes	High risk	No blinding
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcomes data, LBR was not reported
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias.

Methods	RCT, multi‐centre (4 US centres), open‐label, parallel design
Participants	80 women undergoing IVF/ICSI Inclusion criteria: < 39 years of age, day 3 FSH level of < 10, E2 level of < 60 pg/mL, AFC > 5 with a menstrual cycle range of 26 ‐ 34 days, and no more than one previous failed IVF or IVF/ICSI cycle. BMI 19 ‐ 32 kg/m² no hydrosalpinx present by hysterosalpingogram, laparoscopy, or ultrasound within the past year  Male factor infertility cases could be included (ICSI and/or frozen sperm) with the exception of nonobstructive azoospermia. Only one study cycle was allowed Exclusion criteria: history of previous poor response (< 4 follicles and/or an E2 level of < 500 pg/mL on the day of hCG), had taken infertility medications (clomiphene and/or gonadotrophins) within the past month, or had failed to consent to taking OCs, GnRH‐analogues, or gonadotrophins.
Interventions	GnRH antagonist (n = 40): OC (Desogen; Organon USA) on cycle days 2 to 4 for 14 to 28 days + 300 IU/day rFSH SC (adjusted) + 250 µg ganirelix was initiated when a lead follicle obtained a mean diameter of 12 to 14 mm (flexible) GnRH agonist (n= 40): leuprolide (GnRH‐agonist group), 0.5 mg per day during the mid‐luteal phase with approximately a 5‐day overlap with the OCs. Once adequate pituitary desensitisation was achieved the dose of GnRH agonist was reduced to 0.25 mg per day + 300 IU/day rFSH SC (adjusted)  Oocyte maturation triggering: at follicular diameter 16 ‐ 18 mm, 5000 to 10,000 IU of hCG (Pregnyl). In cases at risk of ovarian hyperstimulation syndrome, the physician could give a dose of 5000 IU of hCG Oocyte retrieval: 35 to 36 hours later Embryo transfer: at 3 or 5 days Luteal phase support: progesterone, one centre treated women with P, 25 mg IM, on the day of retrieval, followed by P, 50 mg IM daily, with some women being supplemented with hCG 2,500 IU on days 3 and 6 after retrieval. The other centres prescribed luteal support with a daily dose of P (50 mg IM).
Outcomes	Participants to oocyte retrieval (n = 77)  Days from OCP to oocyte retrieval  Days on OC  Stimulation day 1 E2 (pg/mL)  Recombinant FSH (IU)  Days of recombinant FSH  Stimulation day of ganirelix start  Days of leuprolide or ganirelix  LH day hCG (IU/L)  E2 day hCG (pg/mL)  P4 day hCG (pg/mL)  No of follicles  Follicle sizes  Number of oocytes retrieved  Number of mature oocytes  Number of 2 pronuclear embryos  Number of embryos transferred  Percentage of women with cryopreservation  Embryos cryopreserved/participant with cryopreservation  Number of pregnancies/embryos transferred (%)  Number of pregnancies/cycle started (%)  Number of ongoing pregnancies/embryos transferred (%)  Number of ongoing pregnancies/cycle started (%)  Number of implanted embryos (%)  Number of ongoing twin gestations (%)  Delivered pregnancies
Notes	Women who continued to have elevated E2 levels (> 60 pg/mL) and a cyst were removed from the study. If the E2 level was < 60 pg/mL and the cyst was still present, it could be aspirated and the participant would remain enrolled in the study and begin their recombinant FSH administration on Friday, along with a reduction of the GnRH agonist dose to 0.25 mg per day Women who had a serum E2 level of > 60 pg/mL or a cyst > 20 mm were continued on the same leuprolide dose for another week In women randomised to the GnRH‐antagonist group who had an E2 level of < 60 pg/mL, they could begin recombinant FSH on that Friday (5th day after OC). If they had a cyst > 20 mm, they were withdrawn from the study Number of participants at randomisation: 80 (ganirelix: 40/leuprolide acetate: 40) Number of participants at stimulation: 79 (ganirelix: 38/leuprolide acetate: 41) Number of participants at OPU: 77 (ganirelix: 36/leuprolide acetate: 41)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Dark sealed envelopes (true), randomisation: 1:1 (ganirelix acetate: leuprolide acetate) ratio
Allocation concealment (selection bias)	Low risk	Dark sealed envelopes (true)
Blinding (performance bias and detection bias)   All outcomes	High risk	Not reported clearly
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcomes data
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	RCT, single‐centre, parallel design, randomisation: 1:1 (cetrorelix: triptorelin) ratio
Participants	120 infertile women undergoing IVF/ICSI Inclusion/Exclusion criteria:  Infertile women undergoing IVF regardless of the indications or pre‐stimulatory LH levels
Interventions	GnRH antagonist (n = 57): in the antagonist arm, rFSH from day 2 of the cycle, and when the leading follicle reached 13 mm cetrorelix 0.25 mg (Cetrotide; Serono) was started. The LH levels were checked on the day, when the leading follicle reached 13 mm (LH1) and 21 mm (LH2) (Flexible) GnRH agonist (n = 63): in the agonist arm, triptorelin 3,75 (Diphereline SR 3,75mg; Beaufour Ipsen) was administered on day 20 of the preceding cycle and 14 days later if E2 < 30 pg/mL, stimulation with rFSH (Gonal‐F; Serono) was initiated
Outcomes	Number of FSH ampoules used  Number of oocytes retrieved  Fertilisation rate (%) of all retrieved oocytes  Early cleavage rate (%)  Grade A embryos rate (%)  Number of embryos transferred  Clinical pregnancy rate (%)  LH levels
Notes	Number of participants at randomisation: 120 (cetrorelix: 57/ triptorelin: 63)  Number of participants at stimulation: 120 (cetrorelix: 57/ triptorelin: 63)  Number of participants at OPU: 120 (cetrorelix: 57/ triptorelin: 63)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Reported as a randomised trial without any further details
Allocation concealment (selection bias)	Unclear risk	Not reported clearly
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Not reported clearly
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	No missing outcomes data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	Two‐arm parallel RCT
Participants	60 infertile women undergoing IVF at IVF centre; no further details were reported about participants
Interventions	GnRH antagonist: no details were reported GnRH agonist: no details were given
Outcomes	Only pregnancy rate was reported but type of pregnancy was not defined
Notes	Unclear definition of pregnancy
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No information was reported on random sequence generation
Allocation concealment (selection bias)	Unclear risk	No information was reported on allocation concealment
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	No information was reported on blinding of participants and/or personnel; however, non blinding of outcome assessment may not affect some outcomes of interest as they are objectively assessed
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	No information was reported on incomplete outcome data/attrition
Selective reporting (reporting bias)	Unclear risk	Methods section not detailed enough to make conclusive judgement
Other bias	Low risk	None identified

Methods	RCT, single‐centre, parallel design
Participants	66 infertile women undergoing IVF/ICSI Inclusion/ Exclusion criteria:  Poor responders were classified as patients who had exhibited a poor ovarian response with < 3 mature follicles on a long GnRH agonist protocol in their previous IVF cycles, or those with repeated high basal levels of FSH > 10 IU/l Women with polycystic ovaries were excluded from the study
Interventions	GnRH antagonist (n = 33): OCP (Nordette) 30 µg of ethinyl estradiol and 150 µg of levonorgestrel for 21 days + 300 IU daily rFSH (Gonal‐F) + 0.25 mg SC cetrorelix (Cetrotide) (fixed), multi‐dose GnRH antagonist protocol starting on day 6 of the stimulation (fixed)   GnRH agonist (n = 33): long GnRH agonist protocol, buserelin acetate nasal spray (Suprecur) daily dose of 600 µg starting at the mid‐luteal phase of the preceding cycle + 300 IU daily rFSH (Gonal‐F) (long GnRH agonist)   Oocyte maturation triggering: 10,000 IU of IM hCG (Profasi) when the leading follicles reached 18 ‐ 20 mm together with at least three mature follicles > 16 mm Oocyte retrieval: 36 hrs later. ICSI was performed only in cases with severe male factor or previous fertilisation failure Maximum number of embryo transfer: depending on the number of embryos available, up to three embryos were transferred on day 3 after oocyte retrieval Luteal phase support: IM hCG (Profasi) 2000 IU given every 3 days for four doses starting on the day of oocyte retrieval A clinical pregnancy was established when there was a gestational sac seen on ultrasonography
Outcomes	The main outcome measures were duration of stimulation, consumption of gonadotrophins, cycle cancellation rate, and the number of mature follicles recruited and total oocytes retrieved. The hormone levels throughout the cycle, laboratory outcomes and clinical pregnancy rates were also reviewed
Notes	Number of participants at randomisation: 66 (cetrorelix: 33/buserelin acetate: 33) Number of participants at stimulation: 63 (cetrorelix: 31/buserelin acetate: 32) Number of participants at OPU: 40 (cetrorelix: 19/buserelin acetate: 21) Cycles in which < 3 mature follicles developed, or if the ovaries failed to respond after 10 days of stimulation, were either cancelled or converted to intra‐uterine insemination in patients with patent tube(s).
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Random‐number table (true), randomisation: 1:1 (cetrorelix: buserelin acetate) ratio
Allocation concealment (selection bias)	Low risk	Performed
Blinding (performance bias and detection bias)   All outcomes	Low risk	Blind
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	No missing outcomes data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	Three‐arm randomised controlled trial. Single centre
Participants	61 infertile women (67 cycles) Inclusion criteria: PCOS (ESHRE/ASRM criteria). No other details Exclusion criteria: no details Setting and timing ‐ Seoul, Korea. April 2009 to November 2010 Baseline characteristics: age ‐ antagonist 32.9 ± 2.9 years versus agonist 34.4 ± 3.8 years
Interventions	IVM/IVF with FSH and hCG priming protocol (n = 11 women; 14 cycles) Antagonist multidose flexible protocol (n = 36 women; 39 cycles). Stimulation started on day 2 or 3 and 0.25 mg cetrorelix acetate or 0.25 mg ganirelix acetate administered when follicles > 12 mm or serum E2 > 200 pg/ml Agonist long protocol (n = 14 women; 14 cycles) 0.5 mg buserelin acetate or 0.1 mg leuprolide acetate given from mid‐luteal phase of previous cycle to day of hCG administration 250 micrograms hCG given when lead follicle > 18 mm diameter Oocyte retrieval 36 hours after hCG Dose of gonadotrophin antagonist 1656.7 ± 669.77 versus agonist 2700.0 ± 824.3
Outcomes	OHSS, clinical pregnancy, miscarriage, live birth rate: all reported as 'per cycle' and thus could not be pooled
Notes	Sample size calculation ‐ no ITT analysis ‐ yes Funding ‐ not stated
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	'randomized' no other details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	No details. Unlikely that participants and researchers were blinded but unlikely to affect fertility outcome. Blinding of outcome assessors is unclear
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Data reported on all women analysed
Selective reporting (reporting bias)	Low risk	Outcomes reported including live birth rate
Other bias	Unclear risk	Groups appeared balanced at baseline. Data is per cycle and not per woman randomised and could not be included in the meta‐analysis

Methods	Randomised controlled trial
Participants	64 women undergoing ICSI (first cycle) Inclusion criteria: 37 years or less, first IVF/ICSI cycle, BMI < 30 kg/m2, regular menses, both ovaries present Exclusion criteria: PCOS, severe endometriosis, ovarian cysts assessed by transvaginal ultrasound, basal FSH 10 IU/ml or greater Baseline characteristics: age ‐ antagonist group 32.5 ± 3.0 years versus agonist group 33.2 ± 3.0 years Setting and timing: Center for Human Reproduction, Brazil
Interventions	GnRH antagonist (n = 32) cetrorelix. Ovarian stimulation using 150 to 225 IU recombinant FSH and 75 IU/day recombinant LH for five days starting on day 3. Follicular development monitored on Day 8. rFSH adapted according to ovarian response and rLH increased to 150 IU/day when one or more follicles reached 10 mm or more in diameter. Cetrorelix 0.25 mg/day SC started when at least one follicle was 14 mm or greater in diameter. Administered until day of hCG injection GnRH agonist (n = 32) leuprolide acetate 1 mg/day starting in luteal phase of previous cycle for 14 days. Ovarian stimulation using 150 to 225 IU rFSH and 75 IU/day rLH for 7 days. rFSH adapted according to ovarian response and rLH increased to 150 IU/day when one or more follicles reached 10 mm or more in diameter. Administered until day of hCG injection Oocyte maturation: 250 micrograms recombinant hCG given SC when at least two follicles were 17 mm or greater in diameter Oocyte retrieval: 34 ‐ 36 hours after hCG injection Total dose gonadotrophins: antagonist group 1877.3 ± 817 IU versus agonist group 2185.5 IU
Outcomes	Oocyte morphology. Implantation rate, pregnancy rate (not defined)
Notes	Sample size calculation: yes ITT analysis ‐ yes Funding: no details Data cannot be included in a meta‐analysis as it is unclear if the pregnancy rate refers to a biochemical or clinical or ongoing pregnancy. Another trial Lavorato 2012 reports on 32 women from the same authoring group and centre with the outcomes of DNA fragmentation and apoptosis in granulosa cells. No pregnancy data reported in this paper either
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Double randomisation using computer‐generated number table then lots
Allocation concealment (selection bias)	Low risk	One nurse, blinded to subject identities, performed all the lot draws
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	No evidence of blinding of participants. Blinding of outcome assessors unclear
Incomplete outcome data (attrition bias)   All outcomes	Low risk	All women randomised appear to be analysed
Selective reporting (reporting bias)	Unclear risk	Authors report pregnancy rate but it is not defined, therefore unclear if it is biochemical, clinical or ongoing and cannot be included in a meta‐analysis. Other data is reported per oocyte of which there were 300 per group
Other bias	Low risk	Groups appeared balanced at baseline

Methods	RCT, single‐centre study
Participants	136 consecutive patients undergoing ICSI Inclusion criteria: age 24 ‐ 42 years, baseline FSH level < 10 IU/ml, absence of uterine or ovarian abnormalities or severe endometriosis or polycystic ovary syndrome, no more than three previous IVF attempts and, no oral contraceptive pills taken before the stimulation cycle. Male factor infertility cases, such as number of spermatozoa < 5.0 million/ml and < 30% motility were included. Criteria for cycle cancellation were as follows: 53 follicles with diameter 14 mm after 8– 10 days of stimulation Baseline characteristics: age 34.4 ± 4 vs 34 ± 3.9 yrs. Basal FSH (mIU/ml) 6.4 ± 2.4 vs 5.7 ± 2. Basal E2 (pg/ml) 21.71 ± 3 vs 16.7 ± 9.4. BMI (kg/m²) 23.7 ± 4.1 vs 22.7 ± 3.4
Interventions	GnRH antagonist (n = 67): a daily dose of cetrorelix 0.25 mg (Cetrotide) was administered when a leading follicle reached a diameter of 12 – 14 mm + rFSH (Gonal F) starting on cycle day 2 – 3 at a dose of 225 UI/daily, for the first five days (adjusted) (Flexible protocol) GnRH agonist (n= 69): 0.1 mg triptorelin (Decapeptyl 0.1 mg) were administered subcutaneously daily, starting in the late luteal phase (day 21) of the previous cycle + rFSH starting on cycle day 2 – 3 at a dose of 225 UI/daily, for the first five days (adjusted) Final oocyte maturation: was achieved with 6500 UI of hCG (Ovitrelle) when two or more follicles reached a diameter 18 mm  Oocyte retrieval: 35 – 36 hrs after hCG administration Embryo transfer: 3 embryos on day 2 Luteal phase support: was supplemented with progesterone in oil, 50 mg/ day (Prontogest) starting the day after oocyte retrieval and continuing until 12 weeks' gestation if pregnancy was achieved
Outcomes	Oocyte and embryo grading, implantation rate, clinical pregnancy and ongoing rates
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated list at initiation of stimulation, to receive GnRH antagonist or agonist, by using a free internet software for randomisation (Graphpad Software QuickCalcs)
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias)   All outcomes	Low risk	The embryologist scoring the embryos was blinded to the study groups
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	Outcomes were reported in a pre‐specified manner
Other bias	Low risk	Baseline characteristics balanced in both groups

Methods	RCT, single‐centre
Participants	60 women (high responders), aged 20 – 39 years , normal basal FSH concentration ≤ 10.0 IU/L), and undergoing their first cycle of IVF with either PCOS or PCOM (defined according to the Rotterdam consensus guidelines (Rotterdam 2004)) or undergoing a subsequent cycle with a history of high response in a previous IVF cycle. Participants were recruited for the trial for only one cycle Exclusion criteria: women with hypogonadotrophic hypogonadism were excluded Baseline characteristics: age (yrs) 32.0 ± 3.7 vs 33.1 ± 3.6, BMI (kg/m2) 28.3 ± 7.1 vs 30.7 ± 6.4. Baseline serum FSH (IU/L) 5.4 ± 1.8 vs 5.3 ± 1.2
Interventions	Study group: OCPs for 21 days + 112 ‐ 225 IU/day rFSH + ganirelix acetate when the dominant follicle ≥ 14 mm (Flexible multiple‐dose protocol) Control group: OCP for 25 days overlapping with 1 mg leuprolide acetate (Lupron), then reduced to 0.5 mg once down‐regulation was achieved (Low‐dose long GnRH agonist protocol) + 112 ‐ 225 IU/day rFSH Oocyte maturation triggering: when 2 ‐ 3 leading follicles were > 18 mm in diameter Study group: GnRH agonist, 1 mg approximately 12 hours after the last dose of ganirelix Control group: 3300 to 10,000 IU hCG (Profasi) Oocyte retrieval: 35 hours later, followed by IVF/ ICSI Maximum number of embryos transferred: 3 Luteal phase support: study group: 50 mg IM P in oil daily + 0.1 mg transdermal E2 patches every other day; control group: 50 mg IM P in oil daily  Follow up: an ultrasound scan was carried out five to six weeks after oocyte retrieval to determine the viability of the pregnancy. A second ultrasound was performed at 12 weeks’ gestation to confirm any ongoing pregnancy (positive heart beat)
Outcomes	OHSS, implantation rate, number of oocytes retrieved, proportion of mature oocytes retrieved, fertilisation rate, mid‐luteal phase mean ovarian volume (MOV), clinical and ongoing pregnancy rates, and luteal phase serum E2 and P levels
Notes	The diagnosis of OHSS was based on the criteria by Golan et al
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random numbers. To ensure similar distribution of previous high response in the two groups, separate randomisation schedules were drawn up for women undergoing their first cycle and for women with a previous high response by the use of stratified randomised blocks
Allocation concealment (selection bias)	Low risk	Research nurse used a series of consecutively numbered sealed opaque envelopes
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	RCT, multi‐centre (12 centres, 9 countries), Europe and Middle East, multi‐national, open‐label, parallel
Participants	321 infertile couples undergoing ovarian stimulation for IVF‐ET with or without ICSI with all causes of infertility Inclusion criteria: healthy female partners of infertile couples, age at time of screening ≥ 18 but < 39 years, a body mass index (BMI) between 18 and 29 kg/m², a regular menstrual cycle, and willing to give written informed consent Age: not stated Duration of infertility: ganirelix 4.3 years, triptorelin 4.1 years FSH: ganirelix 5.8 IU/ml, triptorelin 2.8 IU/ml BMI: not stated
Interventions	GnRH antagonist (n = 215): 150 IU rFSH (Puregon) (adjusted) + multiple‐dose regimen of 0.25 mg of GnRH antagonist (ganirelix) was administered SC starting from day 6 of stimulation (fixed) GnRH agonist (n=106): mid‐luteal GnRH analogue (triptorelin 0.1 mg SC ) + 150 IU rFSH (Puregon) (adjusted) Oocyte maturation triggering: hCG (Pregnyl) 10,000 IU in 1 ml saline when at least three follicles ≥ 17 mm Oocyte retrieval: About 30 ‐ 36 hours later followed by IVF or ICSI Maximum embryos transferred: 3 Luteal phase support: done according to the centre routine practice Follow up: until ongoing pregnancy
Outcomes	Premature LH surge: (defined as (LH > 10 IU/L) and progesterone level > 1 ng/L) ganirelix group 1 versus triptorelin group 0 Stimulation length: ganirelix group 9 versus triptorelin group 26  rFSH: ganirelix group 1350 IU versus triptorelin group 1800 IU E2 on hCG: ganirelix group 1090 pg/ml versus triptorelin group 1370 pg/ml Number of oocytes retrieved: ganirelix group 7.9 ± 5.1 versus triptorelin group 9.6 ± 6.8 Number of embryos obtained: ganirelix group 4.0 ± 3.0 versus triptorelin group 4.7 ± 3.0 Number of embryos transferred: not mentioned  Implantation rate: ganirelix group 22.9 versus triptorelin group 22.9 Clinical preg/cycle: ganirelix group 32.3 versus triptorelin group 37.8 Clinical preg/ET: ganirelix group 35.8 versus triptorelin group 41.7 Ongoing pregnancy rate: ganirelix group 31.4 versus triptorelin group 33.9 Cancellation: ganirelix group 22 versus triptorelin group 15 Miscarriage: ganirelix group 10.3 versus triptorelin group 11.4 Ectopic: ganirelix group 2 versus triptorelin group 0 OHSS: ganirelix group 4 versus triptorelin group 1 Severe OHSS: only one case ganirelix group Local reaction: ganirelix group 11.9 versus triptorelin group 24.1
Notes	Number of participants at randomisation: 355 (ganirelix 236/triptorelin 119) Number of participants at stimulation: 334 (ganirelix 226/triptorelin 108) Number of participants at OPU: 319 (ganirelix 214/triptorelin 105) Incidence of multiple pregnancies was not mentioned in the table of outcomes and was not clear in the text The study authors used the estimated difference of ganirelix and buserelin in ongoing pregnancy rate compared with the margin of 5%. And for cumulus‐oocyte complexes, the estimated treatment difference was compared with the equivalence margin of 3 oocytes Centre‐adjusted analysis was done for all outcomes except miscarriage, ectopic and ovarian hyperstimulation syndrome
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Interactive response voice system, stratified randomisation, 2:1 randomisation ratio
Allocation concealment (selection bias)	Low risk	Adequate
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcomes data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Unclear risk	Insufficient information to make a conclusive judgement

Methods	RCT, multi‐centre (20 centres), open‐label, parallel design
Participants	730 Infertile couples undergoing ovarian stimulation for IVF‐ET with or without ICSI with all causes of infertility Baseline characteristics: age ganirelix 31.9 ± 3.6, buserelin 31.9 ± 3.8, duration of infertility: ganirelix 4.5 ± 2.7, buserelin 4.4 ± 2.7, FSH: ganirelix 7.7, buserelin 8.4, BMI ganirelix 23 ± 2.9, buserelin 23 ± 2.7
Interventions	GnRH antagonist (n= 486): rFSH (Puregon) was started at fixed daily dose of 150 IU for five days and the dose was adjusted according to response + multiple‐dose regimen of 0.25 mg of GnRH antagonist (ganirelix) was administered SC starting from day 6 of hMG treatment (fixed) GnRH agonist (n= 244): mid‐luteal GnRH analogue (buserelin 0.6 or 1.2 mg four times daily intranasally) + rFSH (Puregon) was started at fixed daily dose of 150 IU for 5 days and the dose was adjusted according to response IVF was done in 357 cases, ICSI was done in 291 cases and 10 cases had both IVF and ICSI Luteal phase support: was done according to the centre's routine practice
Outcomes	Premature LH surge defined as (LH > 10 IU/L) and progesterone level > 1 ng/L  Stimulation length  Number of hMG ampoules  E2 on hCG  No of oocytes retrieved  No of embryos obtained  No of embryos transferred  Implantation rate  Clinical pregnancy/OPU  Clinical pregnancy/ET  Miscarriage  Ectopic  OHSS  Moderate or severe OHSS
Notes	Number of participants at randomisation: 730 (ganirelix 486/buserelin 244) Number of participants at stimulation: 701 (ganirelix 463/buserelin 238 ) Number of participants at OPU: 661 (ganirelix 440/buserelin 221) Incidence of multiple pregnancies was not mentioned in the table of outcomes and was not clear in the text Tolerability was not mentioned in the table of outcomes but stated in the text The study authors used the estimated difference of ganirelix and buserelin in ongoing pregnancy rate was compared with the margin of ‐5%. And for cumulus‐oocyte complexes, the estimated treatment difference compared with the equivalence margin of ‐3 oocytes Centre‐adjusted analysis was done for all outcomes except miscarriage, ectopic and ovarian hyperstimulation syndrome
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Interactive response voice system (true), 2:1 randomisation ratio
Allocation concealment (selection bias)	Low risk	Adequate
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcomes data, LBR not addressed by the study
Selective reporting (reporting bias)	Unclear risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	Randomised controlled trial, single centre
Participants	144 women Inclusion criteria: no specific details but included women who had had moderate or severe OHSS or who had been at risk of OHSS during their first IVF/ICSI cycle with a mid‐luteal long agonist protocol Exclusion criteria: no details Setting and timing: Italy; no details of timing Baseline characteristics: not stated
Interventions	Antagonist ‐ cetrorelix 0.25 mg/day starting on day 3 of the menstrual cycle Agonist ‐ triptorelin 0.1 mg/day starting on day 21 of the menstrual cycle Ovarian stimulation was achieved with rFSH initiated on day 3 of the cycle at a maximum dose of 150 IU and dose adjusted depending on ovarian response Luteal phase support ‐ with micronised progesterone vaginal gel (no other details) Follow‐up ‐ followed‐up to live birth
Outcomes	Live birth, clinical pregnancy, cancellation rate, oocytes retrieved
Notes	As no denominators for groups are given, the data cannot be included in a meta‐analysis
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details
Allocation concealment (selection bias)	Unclear risk	No details
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Open label but blinding unlikely to effect fertility outcome. No details of blinding of outcome assessors
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	Although the abstract states that there were 144 women randomised, there are no other denominators to indicate how many women were allocated to each group. No details on withdrawals or losses to follow‐up
Selective reporting (reporting bias)	Unclear risk	Conference abstract only. Outcomes are not pre‐specified. OHSS not reported
Other bias	Unclear risk	Conference abstract only. Groups were reported as being similar at baseline

PERMALINK

Gonadotrophin‐releasing hormone antagonists for assisted reproductive technology

Hesham G Al‐Inany

Mohamed A Youssef

Reuben Olugbenga Ayeleke

Julie Brown

Wai Sun Lam

Frank J Broekmans

Abstract

Background

Objectives

Search methods

Selection criteria

Data collection and analysis

Main results

Authors' conclusions

Plain language summary

Summary of findings

Summary of findings for the main comparison. GnRH antagonist compared to long‐course GnRH agonist for assisted reproductive technology (ART).

Background

Description of the condition

Description of the intervention

How the intervention might work

Why it is important to do this review

Objectives

Methods

Criteria for considering studies for this review

Types of studies

Types of participants

Types of interventions

Types of outcome measures

Primary outcomes

Secondary outcomes

Search methods for identification of studies

Electronic searches

Searching other resources

Data collection and analysis

Selection of studies

1.

Data extraction and management

Assessment of risk of bias in included studies

Measures of treatment effect

Unit of analysis issues

Dealing with missing data

Assessment of heterogeneity

Assessment of reporting biases

Data synthesis

Subgroup analysis and investigation of heterogeneity

Sensitivity analysis

Overall quality of the body of evidence: 'Summary of findings' table

Results

Description of studies

Results of the search

Included studies

Study characteristics

Participants

Intervention

Outcomes

Excluded studies

Risk of bias in included studies

2.

3.

Allocation

Blinding

Incomplete outcome data

Selective reporting

Other potential sources of bias

Effects of interventions

GnRH antagonist versus long course GnRH agonist

Primary outcomes

1.1 Live birth rate per woman randomised

1.1. Analysis.

4.

5.

1.2 Live birth rate per woman randomised ‐ Subgroup analysis: Minimal stimulation

1.2. Analysis.

6.

1.3 Live birth rate per woman randomised ‐ Subgroup analysis: Grouped by trigger

1.3. Analysis.

7.

Methods	RCT, multi‐centre (11 centres, United States and Canada), open‐label, parallel design
Participants	313 infertile couples undergoing ovarian stimulation for IVF‐ET with or without ICSI with all causes of infertility Baseline characteristics: age: ganirelix 33.0 ± 3.4 vs leuprolide 32.8 ± 4.0 Duration of infertility: ganirelix 4.1 ± 3.0 vs leuprolide 3.8 ± 2.6. FSH: ganirelix 7.9 IU/ml vs leuprolide 3.3 IU/ml. BMI: ganirelix 23.0 ± 3.0 vs leuprolide 23.0 ± 3.0
Interventions	GnRH antagonist (n = 205): A multiple‐dose regimen of 0.25 mg of GnRH antagonist (ganirelix) was administered SC starting from day 6 of rFSH treatment up to and including day of hCG administration (Fixed) + rFSH (Follistim) was started at fixed daily dose of 150 IU for five days and the dose was adjusted according to response GnRH agonist (n= 108): mid‐luteal GnRH analogue (leuprolide 1.0 mg SC) to 99 participants of the control group + rFSH (Follistim) was started at fixed daily dose of 150 IU for five days and the dose was adjusted according to response Luteal phase support was done according to the centre's routine practice
Outcomes	Premature LH surge defined as (LH > 10 IU/L) and progesterone level > 1 ng/L  ganirelix group versus leuprolide group Stimulation length ganirelix group versus leuprolide group rFSH: ganirelix group IU versus leuprolide group IU E2 on hCG ganirelix group pg/ml versus leuprolide group pg/ml Number of oocytes retrieved ganirelix group ± versus leuprolide group ± Number of embryos obtained ganirelix group ± versus leuprolide group ± Number of embryos transferred Implantation rate ganirelix group versus leuprolide group Clinical pregnancy/cycle ganirelix group versus leuprolide group Clinical pregnancy/ET ganirelix group versus leuprolide group Ongoing pregnancy rate ganirelix group versus leuprolide group Cancellation ganirelix group versus leuprolide group Miscarriage ganirelix group versus leuprolide group Ectopic ganirelix group versus leuprolide group OHSS ganirelix group 4 versus leuprolide group 1 Severe OHSS: ganirelix 3 cases, leuprolide 2 Local reaction ganirelix group 11.9 versus leuprolide group 24.1
Notes	Incidence of multiple pregnancies was not mentioned in the table of outcomes and was not clear in the text The study authors used the estimated difference of ganirelix and leuprolide in ongoing pregnancy rate compared with the margin of 5% And for cumulus‐oocyte complexes, the estimated treatment difference was compared with the equivalence margin of 3 oocytes Number of participants at randomisation: 313 (ganirelix 208/leuprolide 105) Number of participants at stimulation: (ganirelix 198/leuprolide 99) Number of participants at OPU: (ganirelix 186/leuprolide 95) Centre‐adjusted analysis: not mentioned
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Interactive response voice system (true), 2:1 randomisation ratio, stratified randomisation
Allocation concealment (selection bias)	Low risk	Adequate
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcomes data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	RCT, open‐label, parallel design, single‐centre
Participants	20 participants without specific ovulatory dysfunction aged ≤ 37 who would be submitted to ovarian stimulation
Interventions	Group A (n = 14): 4 mg/day of estradiol valerate was started and continued for 14 days + rFSH (Puregon) was started one day after the end of estradiol valerate in a fixed dose of 150 ‐ 300 UI + ganirelix (Organolutran, Organon) was taken in a dose of 0.25 mg/day when the follicular diameter was ≥ 15 mm, and continued until the day of the hCG administration (Flexible) Group B (n = 6): In the 21st day of the menstrual cycle, a dose of 200 µg of nafarelin acetate was taken through nasal twice a day. After 14 days of administration of the agonist, with the blockage established (menstruation), the administration of recombinant FSH was started in a fixed dose of 150 ‐ 300 IU for a period of five days. Oocyte maturation triggering: 5 –10.000 IU uhCG at least two follicles ≥ 17 mm Maximum number of embryos transferred: 2 ‐ 3 Luteal phase support: not reported
Outcomes	No of oocytes retrieved  Fertilisation rate  Implantation rate  Pregnancy rate
Notes	Number of participants at randomisation: 20 (ganirelix: 14/ nafarelin: 6)  Number of participants at stimulation: N/A  Number of participants at OPU: N/A
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation list, randomisation: 2:1 (ganirelix:nafarelin) ratio
Allocation concealment (selection bias)	Unclear risk	Unclear
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcomes data, LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	Superiority, randomised open‐label, single centre RCT
Participants	360 idiopathic subfertile participants Inclusion criteria: subfertile women aged between 18 and 50 years with BMI between 18 and 30 Exclusion criteria: women with previous ovarian surgery, women with a previous diagnosis of endometriosis, women treated for benign endouterine disease (such as endometrial polyps, submucous myomas, intrauterine synechiae and/or uterine septus) in the six months before IVF cycle, history of abnormalities in thyroid pattern or alteration in basal serum prolactin value and E2 peak at ovulation induction < 13 nmol/l, history of smoking; untreated uterine myomas; absence of major systemic disease such as diabetes, multiple sclerosis, adrenal diseases, karyotype abnormalities, mutations of the cystic fibrosis gene, acquired or inherited thrombophilia and immunological disorders; previous or actual neoplasia; previous chemo and/or radio treatment for neoplasia; severe qualitative and quantitative alteration in partner's semen (according to World Health Organization guidelines); absence of retrieved oocytes at pick‐up and absence of at least one fertilised oocyte Baseline characteristics: age (years) 37.97 ± 3.73 vs. 35.80 ± 4.35
Interventions	GnRH antagonist (n = 90): rFSH (Gonal‐F) with a starting dose (maintained for the first five days) of 100, 225 and 300 UI per day in estimated high, normo and poor responders, respectively, administered in third day after spontaneous menstruation (pending the basal E2 < 0.3 nmol/l) (adjusted) + daily dose of  0.25 mg/0.5 ml ganirelix starting from the TVS detection of at least one follicle > 14 mm in diameter and continued until hCG administration (short protocol) GnRH agonist (n =180): rFSH (Gonal‐F) with a starting dose (maintained for the first five days) of 100, 225 and 300 UI per day in estimated high, normo and poor responders, respectively, administered at achievement of hypothalamic suppression + daily dose (0.1 mg) of triptorelin acetate (long protocol) Oocyte maturation triggering: 250 mg rhCG SC Luteal phase support: low‐dose PG (200 mg vaginal capsule twice daily) or high‐dose PG (200 mg vaginal capsule three times daily plus 100 mg intramuscular daily) or high‐dose PG (200 mg vaginal capsule three times daily plus 100 mg intramuscular daily) in association with valerate E2 (2 mg vaginal tablet twice daily) Follow‐up: Up to ongoing pregnancy
Outcomes	Ongoing pregnancy, clinical pregnancy, mean value of E₂max at ovulation induction, mean value of endometrial thickness at pick‐up day, quality of embryos
Notes	Three‐arm study, excluded short GnRH agonist protocol (n = 90) "After oocyte fertilization, according to the casual envelopes produced by software randomization, in each Group (A, B and C) patients were randomly assigned (with a randomization of 1:1) to one of three different subgroups (A1, A2 and A3; B1, B2 and B3 and C1, C2 and C3) in relation to the different pharmacological LPS starting from the first day after pick‐up subgroups A1 (60 patients), B1 (30 patients) and C1 (30 patients) received low‐dose PG (200 mg vaginal capsule twice daily) subgroups A2 (60 patients), B2 (30 patients) and C2 (30 patients) received high‐dose PG (200 mg vaginal capsule three times daily plus 100 mg intramuscular daily). Subgroups A3 (60 patients), B3 (30 patients) and C3 (30 patients) received high‐dose PG (200 mg vaginal capsule three times daily plus 100 mg intramuscular daily) in association with valerate E2 (2 mg vaginal tablet twice daily)."
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study randomised participants into subgroups using appropriate random sequence generation but randomisation into large groups A, B, C not clearly stated
Allocation concealment (selection bias)	Unclear risk	Method of allocation not reported for the randomisation of participants into large groups A, B, C
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Study is an open label trial. “As limitations we report:… the impossibility to blind patients and clinicians to the treatment…” “All serum sample were analysed by a single laboratory as well all the endometrial thickness measurements were performed by two skilled sonographers blinded to patients’ treatment”
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	Number randomised = 360, number analysed = unclear
Selective reporting (reporting bias)	Unclear risk	All outcomes reported in a pre‐specified manner. However, live birth rate not reported
Other bias	Low risk	None identified

Methods	Single centre RCT
Participants	300 women with PCOS Inclusion criteria: women with PCOS younger than 35 years old and older than 23 years old: where diagnosis of PCOS was based on the Rotterdam 2004 Criteria, so patients with oligomenorrhoea (an irregular cycle duration greater than 45 days or less than 6 menstrual periods per year) and/or anovulation who also had at least one of the characteristics of hyperandrogenism (a hirsutism score of greater than 7 according to Ferriman and Gallwey (Ferriman 1961), and/or an elevated serum testosterone level which is over 0.8 ng/dl and measured in an Immulite One autoanalyser (Bio Diagnostic Products Corp., USA) using the chemiluminescent method) were diagnosed with PCOS after all the other causes of hyperandrogenism were excluded. Couples in their first IVF/ICSI cycles, women with PCOS whose body mass index was lower than 30 kg/m² and higher than 20 kg/m² Exclusion criteria: women with PCOS whose ovaries did not appear polycystic (where having polycystic ovaries identified by ultrasonography was defined as the presence of 12 or more follicles in each ovary measuring 2 – 9 mm in diameter, and/or increased ovarian volume (> 10 ml)) Patients treated with hormonal medications and other oral anti‐diabetics within the previous three months Baseline characteristics: age (years) 27.57 ± 3.54 vs. 27.70 ± 3.59, BMI (kg/m²) 25.74 ± 4.37 vs. 24.97 ± 4.36, duration of infertility (years) 6.24 ± 3.64 vs. 5.85 ± 3.42, FSH (IU/ml) 4.77 ± 1.80 vs. 5.03 ± 1.36, LH (IU/ml) 5.94 ± 4.17 vs. 5.60 ± 3.49, E2 (pg/ml) 42.82 ± 33.62 vs. 38.83 ± 25.02, IVF/ICSI indications: PCOS + male factor (%) 40.7 (61/150) vs. 38.7 (58/150), PCOS only (%) 54.7 (82/150) vs. 53.3 (80/150), PCOS tubal factor (%) 4.7 (7/150) vs. 8 (12/150).
Interventions	GnRH antagonist (n = 150): OCPs (30 μg of ethinyl estradiol (E2) and 3 mg of drosprinone (Yasmin)) for 21 days starting on cycle day 3 prior to the treatment cycle + 150 IU rFSH (Puregon) initiated on day 3 of menstruation after discontinuation of OCPs + 0.25 mg daily SC ganirelix initiated on day 6 of gonadotrophin stimulation until day of hCG administration. (OCP + GnRH fixed antagonist protocol) GnRH agonist (n = 150): OCPs (30 μg of ethinyl estradiol (E2) and 3 mg of drosprinone (Yasmin)) for 21 days starting on cycle day 3 prior to the treatment cycle + 1 mg daily leuprolide acetate (Lucrin) beginning on day 21 of the preceding menstruation (last three tablets of OCP). Dose reduced to 0.5 mg after ovarian suppression was achieved, until the day of hCG + 150 IU rFSH (Puregon) if there were no cysts ≥ 2 cm and the E2 was < 50 pg/ml. (OCP + long GnRH agonist protocol) Oocyte maturation triggering: 10,000 IU hCG when at least three follicles had a maximum diameter of > 17 mm Oocyte retrieval: 35 – 36 h after hCG injection, ICSI was performed after two hours of incubation and embryos were transferred on day 3 Maximum embryos transferred: 3 Luteal phase support: 90 mg/day intravaginal progesterone (Crinone 8% gel) starting after embryo transfer until the 8th gestational week Follow‐up: Up to ongoing pregnancy
Outcomes	Ongoing pregnancy rate, miscarriage rate, OHSS rate, cycle cancellation rate, day 5 E2 level, E2 level at the day of hCG, progesterone level at the day of hCG, endometrium at the day of hCG, duration of COH, total gonadotrophin used, total cost of COH, MII oocyte number, germinal vesicle number, fertilisation rate, grade 1 embryo number, grade 2 embryo number, total transferred embryos, positive hCG rate, biochemical pregnancy rate, implantation rate, cryopreservation rate, multiple pregnancy rate
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	“The 300 eligible patients were randomized into two groups by an allocation sequence generated from a random numbers table and assigned using consecutively numbered opaque, sealed envelopes on the day of initiation of OCP. Study subjects were randomized in blocks of 30; i.e. of every 30 subjects randomized, Fifteen were allocated to the GnRH agonist and Fifteen were allocated to the GnRH antagonist arm in a random manner.”
Allocation concealment (selection bias)	Low risk	“…assigned using consecutively numbered opaque, sealed envelopes on the day of initiation of OCP.”
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Not reported but unlikely to affect measurement of outcome
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Number randomised = 300, number analysed = 300
Selective reporting (reporting bias)	Unclear risk	All outcomes reported in the pre‐specified manner, except that clinical pregnancy listed as outcome measure at protocol but not reported in study. Live birth rate not reported
Other bias	Low risk	None identified

Methods	RCT, two centres, parallel‐group randomised, open‐label, non‐inferiority effectiveness trial
Participants	404 infertile women undergoing IVF/ICSI Inclusion criteria: no previous IVF treatment or had borne a healthy child after previous IVF treatment, were aged younger than 38 years, and had a menstrual cycle length of 25–35 days and a body‐mass index of 18–28 kg/m² Baseline characteristics: age of women (years) 32.9 (3.1) vs 32.8 (3.2), BMI (kg/m²) 23.0 (2.6) vs 23.2 (2.5), Duration of infertility (years) 3.6 (1.9) vs 3.6 (2.1)
Interventions	GnRH antagonist (n = 205): mild ovarian stimulation with gonadotrophin‐releasing hormone [GnRH] antagonist co treatment combined with single embryo transfer (mild protocol) GnRH agonist (n = 199): (stimulation with a GnRH agonist long protocol and transfer of two embryos (long GnRH agonist protocol)
Outcomes	Primary outcome measures: pregnancy and term live‐birth within one year of randomisation; total costs per couple and child up to six weeks after expected delivery; and participant’s discomfort
Notes	Supernumerary high‐quality embryos: cryopreserved and thawed for transfer in a subsequent unstimulated cycle before the start of a new IVF treatment cycle. These frozen‐thawed embryo‐transfer cycles were treated as a part of the previous IVF cycle. In both groups either one or two cryopreserved embryos were transferred, according to the participant’s preference Fund: ZonMw (Netherlands), programme Doelmatigheidsonderzoek
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random blocks of size four and six were stratified by centre
Allocation concealment (selection bias)	Low risk	Numbered sealed envelopes and made available at each centre; envelopes were sequentially allocated to consecutive participants and opened by treating physicians at IVF planning consultations
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free of other source of bias

Methods	Pilot randomised controlled trial, single centre
Participants	60 women Inclusion criteria: indication for IVF/ICSI Exclusion criteria: ovulatory factor (WHO class I‐III), age ≥ 37 years, more than three previous unsuccessful IVF cycles, TESA/TESE cycles, surrogacy cycles and refusal to participate Setting and timing: IVF unit, Israel. August 2012 to July 2013 Baseline characteristics: age ‐ agonist group 28.6 ± 4.3; antagonist group 29.8 ± 4.3
Interventions	Antagonist ‐ programmed to start on a Friday, antagonist (Cetrotide) ‐ no details of dose) was used in a flexible way. Programming achieved with oral estradiol valerate 2 mg twice daily during early follicular phase from day 2 of a spontaneous menstrual cycle until the first Friday following Agonist ‐ Long luteal agonist protocol (triptorelin‐ no details of dose) Mean number of embryos transferred: antagonist: 1.4 ± 0.7 vs agonist 1.2 ± 0.6 Number of ampoules used: antagonist 24.9 ± 8.1 vs agonist 25.5 ± 13.3 Controlled ovarian hyperstimulation initiated with rFSH alone or in combination with hMG. Adjustments made dependant on individual response
Outcomes	Clinical pregnancy is the only prespecified outcome. Also reported on fertilisation rate, embryo quality, number of embryos transferred, amount of FSH, follicular size
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised but no other details
Allocation concealment (selection bias)	Low risk	Allocation using sealed envelopes handled by an administrator not involved in the study
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Open label study but blinding unlikely to effect fertility outcomes
Incomplete outcome data (attrition bias)   All outcomes	Unclear risk	60 women were randomised and nine did not complete treatment (15%). Three chose another fertility unit, three decided to stop fertility treatment, two were screened out during routine laboratory testing and one had a spontaneous extrauterine pregnancy that required surgical intervention and then postponed fertility treatment. The groups that these women were allocated to was not specified 27/31 women in the antagonist group were analysed and 24/29 in the agonist group
Selective reporting (reporting bias)	Unclear risk	Clinical pregnancy rate was the only prespecified outcome although there are more outcomes reported in the results section. OHSS was not reported
Other bias	Low risk	Groups were balanced at baseline

Methods	RCT, university‐affiliated IVF centre, open‐label, parallel design, randomisation: 2:1 (cetrorelix:triptoreline) ratio
Participants	142 infertile women undergoing IVF/ICSI Inclusion criteria: age between 20 to 38 yrs; BMI 19 to 29 kg/m²; history of regular menstrual cycles, ranging from 25 to 35 days; no relevant systemic disease, severe endometriosis, or uterine and ovarian abnormalities; no more than three previous IVF cycles; and no previous IVF cycle with a poor response or ovarian hyperstimulation syndrome
Interventions	Group A: GnRH agonist triptoreline (Decapeptyl) 1 mg/d, SC starting one week before the expected menses (usually cycle day 21) + fixed daily dose of 150 IU rFSH SC (Gonal‐F) Groups B and C: GnRH antagonist cetrorelix (Cetrotide) 0.25 mg/d, SC commencing when the largest follicle had reached a diameter of 14 mm + rFSH was initiated on cycle day 2 (group B) or 5 (group C). (Flexiblle) Oocyte maturation triggering: when the leading follicle had reached a diameter of 18 mm or more and at least three follicles had reached a diameter of 15 mm or more, 10,000 IU hCG (Pregnyl) was administered Embryo transfer: 35 hrs before the planned time of oocyte retrieval followed by IVF with or without ICSI Maximum number of embryos transferred: 2 embryos were transferred at 3 ‐ 5 days Luteal support: intravaginal progesterone (P; Progestan, Organon; 200 mg, three times daily) was given from the day of oocyte retrieval until a urine pregnancy test was performed 17 days later
Outcomes	Included patients (n = 142)  Age (yr)  Body mass index (kg/m2)  FSH day 2/3 (IU/litre)  Inhibin Bday 2/3 (ng/litre)  Participants undergoing oocyte retrieval (n 104)  n (% per started cycle)  Cycle day start cetrorelix  Day hCG  FSH (IU/litre)  LH (IU/litre)  E2 (n mol/litre)  P (n mol/litre)  Number of follicles (10 mm) day hCG  Number of follicles (15 mm) day hCG  Number of oocytes retrieved  Number of embryos  Fertilisation rate per subject (%)  Number of pregnancies (%)  Number of ongoing pregnancies (%)   Number of twin pregnancies (%)
Notes	Number of participants at randomisation: 169 (cetrorelix: NA/ triptoreline: NA)  Number of participants at stimulation: 142 (cetrorelix: 45/ triptoreline: 97)  Number of participants at OPU: 104 (cetrorelix: 38/ triptoreline: 66)
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation
Allocation concealment (selection bias)	Low risk	Schedule assigned via numbered sealed envelopes
Blinding (performance bias and detection bias)   All outcomes	High risk	Not blind
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data, however LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias

Methods	Randomised controlled trial. Single centre
Participants	112 infertile women with PCOS (Rotterdam criteria) Inclusion criteria: PCOS, < 35 years, normal BMI (< 27 kg/m²), normal prolactin, normal thyroid levels, normal semen analysis for male partner Setting and Timing: Department of Infertility, Tehran, Iran. During 2006 Baseline characteristics: age‐ antagonist 27.8 ± 3.4 years versus agonist 29.3 ± 4.2 years
Interventions	All participants had folic acid 1 mg/day before the induction cycle, low‐dose OCP on day 3 of previous cycle and doxycycline 100 mg twice daily for the first 10 days of the previous cycle Antagonist (n = 57) ovarian stimulation with Gonal F 150 IU commenced on day 3. When follicular diameter ≥ 14 mm cetrorelix 0.25 mg/day SC given for three days. HMG given after seventh day of stimulation. Agonist (n = 55) buserelin 0.5 mg SC started on day 21 of previous cycle. Ovarian stimulation with Gonal F 150 IU commenced on day 3 of next cycle and replaced with HMG after the seventh day of stimulation Oocycte maturation triggered when at least two follicles ≥ 17 mm and hCG 10,000 IU given IM Oocyte retrieval 36 to 38 hours after hCG. Luteal phase support ‐ progesterone suppository cyclogest 800 mg daily
Outcomes	Clinical pregnancy, chemical pregnancy, number of oocytes retrieved, number and days of gonadotrophins, miscarriage, multiple pregnancy, OHSS and severe OHSS
Notes	Sample size calculation ‐ no ITT analysis ‐ yes Funding ‐ none stated
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	'Randomized'
Allocation concealment (selection bias)	Unclear risk	'Sequential' no details
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	No details. Unlikely to have been blinded but blinding unlikely to affect fertility outcomes. Blinding of outcome assessors was not reported
Incomplete outcome data (attrition bias)   All outcomes	Low risk	Women randomised were analysed. No losses reported
Selective reporting (reporting bias)	Unclear risk	All outcomes reported. However, did not report on live birth or ongoing pregnancy as an outcome
Other bias	High risk	Women in the agonist group were slightly older at baseline

Methods	RCT phase III, open‐label, single‐centre study
Participants	251 infertile women undergoing IVF/ICSI Inclusion criteria: age at least 18 years but not older than 39 years; and body weight of 40 – 70 kg Baseline characteristics: age (yr) 33.9 ± 4.4 vs 32.3 ± 2.1 vs 31.6 ± 2.4 vs 30.9 ± 2.5 vs 32.1 ± 2.7; BMI (kg/m²) 20.6 ± 1.4 vs 19.0 ± 1.0 vs 19.5 ± 1.1 vs 20.7 ± 2.1 vs 21.1 ± 1.8; Baseline FSH (IU/L) 4.0 ± 1.8 vs 3.7 ± 1.6 vs 3.9 ± 1.3 vs 3.8 ± 1.4 vs 3.6 ± 1.8
Interventions	Down‐regulation Group 1 (n = 86): cetrorelix 0.25 mg/day, cetrorelix was administered from menstrual day 8 until the day of hCG administration. (Fixed) Group 2 (n = 28): cetrorelix 0.2 mg/day Group 3 (n = 30): cetrorelix 0.15 mg/day Group 4 (n = 58): leuprolide acetate 0.5 mg/day, administered on days 21–23 of the previous menstrual cycle Group 5 (n = 49): leuprolide acetate depot 1.88 mg. Single dose leuprolide acetate depot subcutaneous COH: 150 – 225 IU/day rFSH (Gonal‐F) in women < 34 years old, 225 ‐ 300 IU rFSH in women > 34 years Final oocyte maturation triggering: 5000 IU hCG were given when at least three mature ≥ 18 mm follicles were obtained Oocytes retrievals: 36 hrs later Maximum embryo transfer: six embryos were transferred at 72 hrs after IVF/ICSI injection  Luteal phase support: hCG (2000 IU/day) on days 1, 4 and 7 post‐ET and progesterone (400 mg/day; Utrogeston) from day 1 post‐ET Follow up: clinical pregnancy was determined by visualisation of a gestational sac, and fetal viability by ultrasound four weeks post‐ET
Outcomes	Gn dosage, and serum concentration of LH and E2 on the day of hCG administration, retrieved oocyte and embryo numbers, development of OHSS, embryo quality, and pregnancy rate (PR), implantation rate (IR) and abortion rate (AR)
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Reported as a randomised trial without any further details
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data, however LBR not addressed by the study
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Unclear risk	No source of other bias identified

Methods	RCT, multi‐centre (eight European IVF centres), phase IIIb study
Participants	182 infertile women undergoing IVF/ICSI Inclusion criteria: participants needed to have a regular IVF/ICSI indication, a male partner with viable sperm in the ejaculate (testicular biopsy or epididymal sperm was not allowed), aged between 18 and 39 years Exclusion criteria: people with any previous assisted reproduction treatment cycles with less than three oocytes or three or more consecutive ART cycles without a clinical pregnancy or with any contraindication to ART, gonadotrophins or OC pills. People with a significant systemic disease Baseline characteristics: age (years) 32.8 ± 3.8 vs 32.2 ± 4.2. BMI (kg/m²) 23.7 ± 4.0 vs 22.6 ± 3.5. FSH (IU/l) on cycle day 2 or 3 7.2 ± 2.2 vs 7.4 ± 3.3 0. Estradiol (pmol/l) on cycle day 2 or 3 138 ± 55, 148 ± 103
Interventions	GnRH antagonist (n = 91 ): daily OCPs (30 μg ethinyl E2 and 150 μg levonorgestrel) for 21 – 28 days + r‐hFSH 150 – 225 IU (Gonal‐F) according to the study centre’s standard practice (adjusted)+ daily cetrorelix 0.25 mg subcutaneously started on stimulation day 6 and continued up to and including the day of r‐hCG administration. (Fixed) Group 2 (n = 91): daily buserelin, 500 μg, subcutaneously at the mid‐luteal phase of a natural cycle for at least 10 days until down‐regulation was achieved, after which the dose was reduced to 200 μg/day + r‐hFSH 150 – 225 IU (Gonal‐F), according to the study centre’s standard practice (adjusted) Final oocyte triggering: r‐hCG 250 μg (= 6500 IU) (Ovitrelle) was injected as soon as the largest follicle reached a mean diameter ≥ 18 mm and at least two other follicles of a mean diameter ≥ 16 mm Oocyte retrieval: 34 – 38 hrs after r‐hCG administration under ultrasound guidance, followed by a standard IVF or ICSI procedure Maximum number of embryo transfer: no more than two to three embryos were replaced either 2 – 3 days or 5 – 6 (blastocyst transfer) days Luteal phase support: intravaginal natural progesterone (three times daily 200 mg Progestan®, Organon, Oss, The Netherlands) was started as luteal support. This was continued up to a negative pregnancy test or during the first three weeks of pregnancy
Outcomes	Number of oocytes retrieved in IVF/ICSI patients Pregnancy was defined as continuing increase in serum hCG. In that case, four and 10 weeks after embryo transfer, ultrasound was performed to assess the number of fetal sacs and heart activity. Clinical pregnancy was defined as the presence of a fetal sac, with or without heart activity. Ongoing pregnancy as a positive heart activity at a gestational age of 12 weeks
Notes
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated concealed randomisation list. Randomisation was performed by centre
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias)   All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias)   All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	The study protocol was not available, but it is clear that the published reports included most expected outcomes
Other bias	Low risk	The study appears to be free from other sources of bias