Eftekhar 2012.

Methods	Single‐centre, 2‐arm, parallel RCT
Participants	130 infertile women who were candidates for FET Inclusion criteria: women who had undergone IVF or ICSI with cryopreservation of excess embryos and fresh cycles with implantation failure. Exclusion criteria: aged > 38 years, BMI > 30 kg/m2, history of endocrine disorders and severe endometriosis Baseline characteristics similar in both groups
Interventions	HT (65 women) All women received estradiol valerate 6 mg/d orally from day 2 of menstrual cycle and progesterone in oil 100 mg IM when the endometrial thickness reached 8 mm ET was performed 3 days after the beginning of progesterone administration. Estradiol and progesterone were continued until the 10th week of gestation HT plus HCG (65 women) As for HT and in addition, women received an HCG 5000 IU injection on the first day of progesterone administration and the day of ET. Embryo thawing was performed 2 days after the first progesterone injection. Embryos were transferred 1 day after thawing using a Labotect catheter (Labotect, Gotting, Germany).
Outcomes	Miscarriage Ongoing pregnancy Clinical pregnancy
Notes	No outcome data available
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random sequence
Allocation concealment (selection bias)	Unclear risk	No information reported on allocation concealment
Blinding (performance bias and detection bias) All outcomes	Unclear risk	No information reported 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	Unclear risk	No information reported on withdrawals or losses to follow‐up, or both
Selective reporting (reporting bias)	Low risk	Outcome measures were prespecified in the methods section
Other bias	Low risk	Baseline characteristics similar in both group