Blot 1981.

Methods	This was a RCT conducted on women coming for antenatal examination in Paris. Each women was given a bottle containing iron or a combination thereof with folic acid. The 2 groups of women were totally comparable on their baseline characteristics.
Participants	All women attending for the compulsory antenatal examination at the end of 6th month of pregnancy (n = 109).
Interventions	Group1: iron 105 mg (n = 55). Group2: iron 105 mg + folic acid 350 mg (n = 54).
Outcomes	Pre‐delivery haemoglobin levels (n = 109).
Notes	All women were given ascorbic acid 500 mg. Study population was generally from upper social class which may lead to underestimation of nutritional deficiencies.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "patients were given bottle of 90 tablets, contained either iron or the combination of iron with folic acid". Comment: probably not done.
Allocation concealment (selection bias)	Low risk	Bottle of tablets without the awareness of intervention type was given to patients.
Blinding (performance bias and detection bias) All outcomes	Low risk	Neither the patient nor the obstetrician was aware of the nature of treatment.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Data on exclusion with its reason were not described in the text. Attrition (45.5%) with reasons were reported.
Selective reporting (reporting bias)	Low risk	Study appears to be free of selective reporting.
Other bias	Unclear risk	No other bias identified but insufficient information available to fully assess this 'Risk of bias' domain.