Agarwal 2016.

Methods	Unit of randomization: pregnancy Method of randomization: unclear Timing of randomization: unclear Blinding: no Power calculation: unknown Number of centers: 1 90 women total enrolled; 30 randomized to progesterone, 30 to nothing, and 30 healthy controls; 300 women analyzed Source of funding: All India Institute of Medical Science
Participants	Women with a history of ≥ 2 consecutive miscarriages of unknown cause. Euthyroid Exclusion: history of repeated miscarriages of known cause Age: 21‐40 Location: India Timing and duration: August 2013‐unknown
Interventions	200 mg oral micronized progesterone twice daily up until 16 weeks' gestation Control: no intervention Healthy control group
Outcomes	Cytokines, "perinatal outcome", occurrence of obstetric complications like ICP, pre‐eclampsia
Notes	Trial registry summary from Clinical Trials Registry ‐ India Dates of study: first enrollment 12 August 2013, completion date not specified Funding sources: All India Institute of Medical Sciences, New Dehli (government medical college) Declarations of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Random number table."
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Only intervention group took drug but unlikely that knowledge of assignment would influence outcomes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not stated but unlikely that knowledge of assignment would influence outcomes
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Only abstract results from trials registry
Selective reporting (reporting bias)	Unclear risk	Unclear. Only abstract results available from trials registry
Other bias	Unclear risk	Unclear. Only abstract results available from trials registry