Turgal 2017.

Methods	Design: RCT Recruitment method: through assessment of women presented to the hospital Method of randomisation: computerised random number generator program Setting: a university hospital
Participants	Inclusion: women with threatened abortion and with presence singleton pregnancy and live embryo, before 9 weeks of gestation Exclusion: non viable fetus, twin pregnancy, presence of subchorionic haematoma and history of hypertension, diabetes mellitus, severe hepatic disorders, uterine leiomyoma, congential uterine anomaly and recurrent pregnancy loss Particpants randomised: 83
Interventions	Intervention group: (42 women) oral micronised progesterone, 400 mg/d for 4 weeks Control group: (41 women) placebo
Outcomes	Primary outcome: fetal‐placental volume change Secondary outcomes: miscarriage rate live birth rate preterm birth birthweight LBW intrauterine growth restriction neonatal respiratory distress syndrome
Notes	Journal: Journal of clinical Utrasound Year of publication: 2017 Country: Turkey Income status of the country: upper middle‐income Source of funding: not mentioned Conflict of interest: not mentioned
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computerised random number by using generator program
Allocation concealment (selection bias)	Unclear risk	Unclear
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Placebo was used
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Outcome is not affected by blinding of outcomes assessors
Incomplete outcome data (attrition bias) All outcomes	Low risk	Incomplete outcome data in 12 women (14.5%), equal in both groups
Selective reporting (reporting bias)	Low risk	All the prespecified outcomes were addressed
Other bias	Low risk	No other biases