El‐Toukhy 2004.
Methods | Single‐centre parallel RCT | |
Participants | 234 women Inclusion criteria: women with functioning ovaries and regular menstrual cycles who had surplus embryos frozen following fresh ET in a cycle of IVF or ICSI Exclusion criteria: FET originating from donated oocytes and women with irregular cycles. Number of transferred embryos per woman: HT group 2.2 ± 0.6, HT plus GnRHa group 2.3 ± 0.6 Baseline characteristics were similar in the 2 groups Infertility cause: similar (variety of causes) |
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Interventions |
HT group (117 women) Estradiol valerate 6 mg/d/tablet started on day 1 of menstruation HT plus GnRHa group (117 women) Buserelin nasal spray was started in mid‐luteal phase (day 21) of cycle. On day 1 of subsequent cycle, oral E2 initiated as 6 mg/d in 2 divided doses In both groups, E2 dose continued for 12‐14 days then endometrial thickness was assessed by US. If endometrial thickness was < 8 mm, E2 dose was increased to 8 mg/d for further 7‐12 days Once 8 mm endometrial thickness had been confirmed, micronised progesterone pessaries 400 mg twice daily were commenced. GnRHa was stopped at this stage. There was no endocrine or US monitoring of ovulation. Embryos were transferred on day 3 of progesterone initiation. Progesterone use was for 2 weeks following FET. Pregnant women were advised to continue E2 and progesterone supplement up to 12th gestational week. |
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Outcomes | Clinical pregnancy rate per woman Miscarriage rate per clinical pregnancy Live birth rate per woman Cycle cancellation rate per woman Endometrial thickness prior to FET |
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Notes | Miscarriage rate per clinical pregnancy was used to calculate miscarriage rate per woman. | |
Risk of bias | ||
Bias | Authors' judgement | Support for judgement |
Random sequence generation (selection bias) | Low risk | Computer‐generated random list |
Allocation concealment (selection bias) | Unclear risk | Methods used in concealing the allocation not reported |
Blinding (performance bias and detection bias) All outcomes | Unclear risk | No reports on blinding of participants and personnel, although blinding of outcome assessor could not have influenced some of the reported outcome measures |
Incomplete outcome data (attrition bias) All outcomes | Low risk | Analysis reported to have been performed on an ITT basis. ITT was not fully defined but it was apparent from 1 of the result tables that all participants randomized were included in data analysis (other aspects of ITT could not be verified) |
Selective reporting (reporting bias) | Low risk | Data reported on all the outcomes prespecified in the methods section. |
Other bias | Low risk | No other potential source of bias found. |