S Africa 1985.

Methods	A double‐blind, randomised, placebo‐controlled. It was a 4‐arm trial.
Participants	127 black women before 20th week of pregnancy for antenatal medical care with expectation of spontaneous vaginal delivery and a willingness to attend the clinic at Kwa‐Mashu Polyclinc near Durban, South Africa, daily until delivery to eat dietary supplements under supervision were selected for the study. Free transportation was provided daily to the clinic. At entry, each woman had a detailed medical and socioeconomic history, physical examination, assessment of the week of pregnancy by date of LMP and ultrasonic measurements. Serum levels of proteins, cholesterol, triglyceride, carotene, vitamin A, vitamin C, phosphorus, alkaline phosphatase, calcium and magnesium were also measured. An experienced dietitian calculated dietary intake before starting the supplements from a 24‐hour, quantitative, dietary recall history. The recorded diets were deficient in energy, protein, the B vitamins, calcium and iron among these women. Women in the zinc group in this study had a significantly lower mean weight than the women in the placebo group.
Interventions	Women were randomly assigned to 1 of 4 groups. Before supplementation the women in 3 of the 4 groups had similar body weights. Primigravidas were equally distributed by chance among the 4 groups. Group 1 received placebo pills and group 2, 30‐90 mg zinc gluconate daily. Groups 3 and 4 were given food supplements from the 20th week of pregnancy to delivery, Monday through Friday. These supplements were designed to correct dietary deficiencies detected in the dietary recall histories, particularly deficiencies in energy and protein. Group 3 women received a high bulk supplement, a mixture of beans and maize in a 1.2 : 1 ratio as mush with added vitamins. Group 4 women received a low bulk supplement, a porridge containing 100 g dry skimmed milk, maize flour, vitamins and minerals. It differed from the group 3 supplement in its 36 g of animal protein and in its higher levels of several vitamins and calcium. Group 1: placebo (n = 33). Group 2: zinc: zinc gluconate 30‐90 mg daily (n = 32). Group 3: high food supplement (n = 31). Group 4: low food supplement (n = 31).
Outcomes	Maternal outcomes Levels of constituents of serum samples: Albumin, cholesterol, triacylglycerol, carotene, vitamin A, vitamin C, phosphorus, alkaline phosphatase, calcium, magnesium. Neonatal outcomes Gestational age at birth; birthweight.
Notes	Adherence: figures for adherence were not given, but the authors commented that it was high, due to free transportation to the clinic where the supplements or placebo were consumed under supervision. Groups given dietary supplements are not included in the analysis.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of sequence generation not reported.
Allocation concealment (selection bias)	Low risk	Randomisation by numbered packets prepared at the pharmacy, code held by pharmacy until the end of the study.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding by use of placebo until end of study.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Not reported but likely to have been blinded due to use of placebo.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Losses to follow‐up: 10% (exact figures not given) of women before giving birth, principally due to moving out of the area.
Selective reporting (reporting bias)	Unclear risk	Not enough information to make this judgement. No information on if the protocol had been published prior to the trial.
Other bias	Unclear risk	No apparent risk of other bias.