Ghosh 2014

Methods	Unit of randomization: pregnancy Method of randomization: unclear Timing of randomization: before the 13th week of gestation Blinding: single Power calculation: no, listed as pilot study Number of centers: 1 ‐ tertiary infertility care unit in India 101 women randomized 2 women excluded 133 women analyzed (added controls without miscarriage history) Source of funding: not stated
Participants	Women with ≥ 3 miscarriages in the first trimester (up to 12 weeks' gestation) followed by a spontaneous conception confirmed by viable fetus on ultrasound Exclusions: abnormal thyroid, prolactin, or any other medication in the last 3 months. Also excluded if there was an apparent cause of miscarriages by multiple lab and chromosomal testing. Also excluded luteal phase defects diagnosed by midluteal serum progesterone. Age: 23‐40 years Location: India Timing and duration: taken up to 12 weeks
Interventions	Intervention: 10 mg oral dydrogesterone twice daily (50 women) or 100 mg micronized vaginal progesterone three times daily (51 women), taken up to 12 weeks Control: women without a history of miscarriage (32 women)
Outcomes	Uterine doppler blood flow parameters, ongoing clinical pregnancy (at least 1 viable fetus at 28 weeks' gestation), viable delivery, miscarriage rates
Notes	Emailed contact author to ask about "ongoing pregnancy" group. if still pregnant at time of analysis, only able to utilize miscarriage data Dates of study: not stated Funding sources: "no financial support received" Declarations of interest: trial authors report "no conflicts of interest"
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Study co‐ordinator did a "simple randomization"
Allocation concealment (selection bias)	Low risk	Sequentially numbered sealed envelopes prepared by study co‐ordinator
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants were not blinded due to different routes of administration but study personnel were "unaware of the type of protocol being used" and considered single‐blinded but unlikely that knowledge of assignment would influence outcomes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Study personnel unaware of protocol
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 women excluded from analysis for adequate reasons
Selective reporting (reporting bias)	Low risk	Reported on outcomes collected
Other bias	Unclear risk	"ongoing pregnancy" group still pregnant at analysis so could not determine outcome for them other than that they did not have a miscarriage