A randomized, placebo-controlled trial of the effect of zinc supplementation during pregnancy on pregnancy outcome in Bangladeshi urban poor.
What this study found
Zinc supplementation did not improve pregnancy or birth outcomes. In the zinc group, mean birth weight was 2513 ± 390 g versus 2554 ± 393 g with placebo, and there were no significant differences in gestational age, infant length, head circumference, chest circumference, or MUAC. Low birth weight, prematurity, and small for gestational age rates were also similar between groups, and serum zinc at 7 months gestation was 15.9 ± 4.4 mol/L versus 15.2 ± 4.3 mol/L, P = 0.065. The authors concluded that zinc alone is unlikely to reduce low birth weight in this population.
- Study & population
- Randomized, double-blind, placebo-controlled trial in pregnant women from the urban slums of Dhaka, Bangladesh.
- Intervention
- Pregnant women in the active arm received 30 mg elemental zinc per day as oral zinc acetate tablets, taken daily from enrollment in the last two trimesters until delivery.
- Key limitation
- A substantial number of participants were lost before delivery, and birth-weight analyses included fewer singleton infants than were randomized.
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Open PDFOriginal abstract
BACKGROUND Maternal zinc supplementation has been suggested as a potential intervention to reduce the incidence of low birth weight in developing countries. To date, placebo-controlled trials have all been performed in industrialized countries and the results are inconsistent. OBJECTIVE The objective of this study was to evaluate whether zinc supplementation in Bangladeshi urban poor during the last 2 trimesters of pregnancy was associated with pregnancy outcome. DESIGN We conducted a double-blind, placebo-controlled trial in which 559 women from Dhaka slums, stratified by parity between 12 and 16 wk of gestation, were randomly assigned to receive 30 mg elemental Zn/d (n = 269) or placebo (n = 290). Supplementation continued until delivery. Serum zinc was estimated at baseline and at 7 mo of gestation. Dietary intake was assessed at baseline and anthropometric measurements were made monthly. Weight, length, and gestational ages of 410 singleton newborns were measured within 72 h of birth. RESULTS At 7 mo of gestation, serum zinc concentrations tended to be higher in the zinc-supplemented group than in the placebo group (15.9 +/- 4.4 compared with 15.2 +/- 4.3 micromol/L). No significant effect of treatment was observed on infant birth weight (2513 +/- 390 compared with 2554 +/- 393 g; NS) or on gestational age, infant length, or head, chest, or midupper arm circumference. The incidence and distribution of low birth weight, prematurity, and smallness for gestational age also did not differ significantly after zinc supplementation. CONCLUSIONS Supplementation with 30 mg elemental Zn during the last 2 trimesters of pregnancy did not improve birth outcome in Bangladeshi urban poor. These results indicate that interventions with zinc supplementation alone are unlikely to reduce the incidence of low birth weight in Bangladesh.