Kaur 1991.

Methods	Randomised controlled trial.
Participants	50 pregnant women with similar socioeconomic conditions in India.
Interventions	Participants were randomised into 2 groups: group 1 (n = 25) received orally 2 pharmacological doses of vitamin D˜ (60,000 IU each) in 6th and 7th month of pregnancy; group 2 (n = 25) did not receive any vitamin supplement and served as controls. Health worker cadre: not specified.
Outcomes	Infant: mean birthweight, placental weight and DNA content, total protein and RNA, protein/DNA and RNA/DNA ratios. Laboratory method used for assessment of vitamin D concentrations: not applicable.
Notes	Total dose of supplementary vitamin D during pregnancy: more than 56,000 to 200,000 IU; start of supplementation: 24 and 28 weeks of pregnancy; pre‐gestational BMI (kg/m2): unknown/mixed; supplementation scheme/regimen: monthly; skin pigmentation based on Fitzpatrick skin tone chart (Fitzpatrick 1988): mixed/unknown; latitude: north of Tropic of Cancer; season at the start of pregnancy: unknown. Source of funding: unknown/unreported. Dates of the study and location: not reported dates, India. Declarations of interest among primary researchers (or state where this information is not reported by the trial authors): not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Authors only mentioned that women were randomly selected for trial initially.
Allocation concealment (selection bias)	Unclear risk	The trial did not report the method of concealment. It is assumed that no method was used as one of the groups did not receive any supplementation.
Blinding of participants and personnel (performance bias) All outcomes	High risk	The trial did not report if it was blinded. It is assumed that it was not blinded to participants as one of the groups did not receive any supplementation.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	There is insufficient information to permit judgement.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	The number lost to follow‐up was not reported in results.
Selective reporting (reporting bias)	Unclear risk	The total number of participants that completed the study was not specified in results.
Other bias	Low risk	The study appears to be free of other sources of bias.