Prenatal zinc and vitamin A supplementation : a study on the impact of prenatal micronutrient supplementation in rural Indonesia

Abstract: Objectives: To study the effects of prenatal zinc and vitamin A supplementation on birthsize, neonatal morbidity, infant mortality, and growth in children up to two years of age. Subjects and Methods: From September 1995 to December 1999 pregnant women inPurworejo District, Central Java, Indonesia with gestational age <17 weeks (n=2173) wererecruited to and participated in a community-based, individually randomized, placebo controlled,double blinded study aiming to evaluate the impact of supplementation (vitamin A,zinc, vitamin A + zinc) during pregnancy on maternal morbidity and pregnancy outcomes. Weanalyzed secondary data from that study regarding birth size, neonatal morbidity and infantmortality of the 1956 infants born alive. A subsample of infants (n=343) was followed until 2years of age concerning growth, feeding practices and morbidity. Outcomes were tested usingthe chi-square test, ANOVA, ANCOVA, and Cox’s proportional hazard function. Results: Birth weights in the zinc [mean ±Standard deviation (SD): 3.16 ± 0.52 kg], vitaminA (3.08 ± 0.46 kg) or the combined vitamin A and zinc (3.10 ± 0.59) groups did not differ fromplacebo (3.09 ± 0.50 kg) after adjustment for maternal pre-pregnancy weight, weight gainduring pregnancy, and parity (P=0.70). Birth lengths of infants born to mothers supplementedwith zinc or vitamin A were in average 0.3 cm and 0.2 cm longer than those in the placebogroup after adjustment for maternal height, pre-pregnancy weight, weight gain during pregnancy,and parity (P=0.04). The impact of prenatal supplementation on infant mortality andneonatal morbidity was not significant. There was a small effect of prenatal vitamin A supplementationon postnatal growth in height-for-age z-score (HAZ). The absolute differencesbetween the vitamin A only and vitamin A + zinc groups at 3 and 9 months were 0.34 SD and0.37 SD, respectively, and the absolute difference between the vitamin A only and zinc onlygroups at 18 months was 0.31 SD. Defining growth faltering as downward crossing of ≥2 majorpercentile lines, 50-75% of the children were faltering within 9 months of age, whereas 17%and 8% were <-2 SD for growth in weight-for-age z-score (WAZ) and HAZ, respectively.Prenatal supplementation did not reduce the prevalence of growth faltering. Conclusions: Prenatal vitamin A and zinc demonstrates a small but significant impact onbirth length, but it does not have any protective effect on infant mortality and neonatal morbidity.Prenatal vitamin A supplementation had a small but significant effect on postnatallength growth until 18 months of age, but no effect on weight gain, growth rate and it did notreduce the prevalence of growth faltering.