The effect of zinc supplementation on pregnancy outcome: a randomized controlled trial

Abstract

Objectives: This study aimed to evaluate the impact of prenatal zinc supplementation on pregnancy outcomes.

Methods: A randomized controlled trial with equal randomization (1:1) was conducted on 540 pregnant women in Rasht, Iran from January 2010 to January 2012. Participants were randomly assigned to receive a daily supplement including 400-µg folic acid and 30-mg ferrous sulfate, with or without 15-mg zinc sulfate from the 16th week of gestation until delivery.

Results: Mean difference of birth weight between the two groups was not significantly different (3262 ± 390 g in the zinc, 3272 ± 403 g in the no-zinc groups) (p = 0.780). There were no significant differences between the two groups in terms of means of head circumference (p = 0.999), length (p = 0.848), and gestational age at birth (p = 0.057) incidences of low birth weight (p = 0.863), macrosomia (p = 0.642), and the Apgar score >7 at 5 min (p = 0.999), incidences of preterm delivery (p = 0.999), pre-eclampsia (p = 0.835), premature rupture of membranes (p = 0.630), and spontaneous abortion (p = 0.772). Abruption of placenta, amnionitis, stillbirth, and intrauterine death were not observed.

Conclusion: Based on our findings, 15-mg zinc supplementation daily from 16 weeks of pregnancy until delivery cannot improve pregnancy outcomes.

• Birth weight
• maternal outcome
• neonatal outcome
• zinc supplementation

Acknowledgements

The authors acknowledge with grateful appreciation the financial support provided by the Research Deputy at the Guilan University of Medical Sciences. We sincerely appreciate the participation of pregnant women in this project.

Declaration of interest

This study was based on a thesis submitted by the Sadeghi H., medical student at the Guilan University of Medical Sciences. The authors declare that they have no conflicts of interest.