Mounce 2015.

Methods	Single‐centre, 2‐arm, parallel, open‐label RCT
Participants	159 women undergoing FET cycle Inclusion criteria: women were eligible to participate if they were aged < 40 years at the time their embryos were frozen, had at least 1 blastocyst or 2 cleavage‐stage embryos in storage, had regular ovulatory cycles and ≤ 2 previous FET cycles Exclusion criteria: not reported Baseline demographic and infertility characteristics similar between the 2 groups
Interventions	Natural cycle (80 women) Women had a US assessment between day 10 and day 13 of their cycle to confirm follicular growth and endometrial thickness, followed by additional US monitoring in subsequent days if necessary. On detection of LH surge, unit was informed and ET scheduled for up to 1 week later, depending on the stage of embryo development at freezing (i.e. day‐2 cleavage embryos, day‐3 cleavage embryos or day‐5 blastocysts). HT plus GnRHa (79 women) Women commenced daily nasal administration of the GnRHa nafarelin 400 mg twice daily on day 21 of their menstrual cycle until advised to stop, depending on stage of embryo, before the ET procedure. Once down‐regulation was confirmed, women started oral administration of E2 2 mg/d for endometrial preparation, which was increased by a step‐up protocol to 6 mg/d. Women commenced luteal support via vaginal administration of progesterone pessaries 400 mg twice daily according to the proposed day of FET; women with embryos cryopreserved at the cleavage day‐2 stage started pessaries 2 days before the transfer day; women with cryopreserved day‐3 embryos started pessaries 3 days before; and women with cryopreserved blastocysts started their pessaries 5 days before. ET was correspondingly scheduled for up to 1 week after the scan, depending on embryo stage
Outcomes	Live birth per woman Clinical pregnancy rate per woman Multiple pregnancy rate per woman
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Randomisation carried out using a minimisation algorithm
Allocation concealment (selection bias)	Unclear risk	No information reported on allocation concealment
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Open‐label RCT but non‐blinding of outcome assessors may not have affected some of the outcome measures as they were objectively assessed.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data were analyzed on the basis of ITT, i.e. all women randomized were included in data analysis.
Selective reporting (reporting bias)	Low risk	Outcome measures were prespecified in the methods section.
Other bias	Low risk	Baseline demographic and infertility characteristics were similar between the 2 groups.