Association between improved maternal diet before and during pregnancy and increased birth weight of infants
Low birth weight (LBW) poses a significant public health burden on undernourished populations, especially in low- and middle-income countries. Intrauterine growth restriction is the predominant cause of LBW. Low birth weight is associated with increased perinatal mortality as well as reduced cognition and stunting during childhood. A study published in the American Journal of Clinical Nutrition aimed to evaluate the effect of improved maternal diet quality over a sustained duration before and during pregnancy on infant birth weight.
In this study, 6513 women intending to become pregnant were randomly assigned to receive either a daily snack made from green leafy vegetables, milk and dried fruits (treatment group) or a snack made from vegetables with low micronutrient content (control group) in addition to their regular diet. The supplementation was started > 90 days before pregnancy and continued until delivery. The birth weights of 1360 newborns were measured at the end of the study.
No overall increase in birth weight was observed in the intention-to-treat analysis (women who became pregnant after starting the supplementation). However, in the per-protocol analysis (women who started supplementation > 90 days before their last menstrual period), a mean 48-g increase in birth weight was noticed in the treatment group along with a 24% reduction in the prevalence of LBW. Greater intervention effect with respect to birth weight and other newborn measurements was noted with higher maternal prepregnant body mass index.
The study limitations included 34% loss to follow-up, lack of monitoring of iron and folic acid supplements intake, low overall compliance to treatment protocol (40%-50%) and reduction in sample size due to inability to measure 32% of newborns.
The study results suggest that nutritional supplementation for > 90 days before conception may result in increased birth weight of infants, provided the mother is not underweight. The findings emphasise the need for different interventions based on the nutritional status of the women.
News Source: Potdar R, Sahariah S, Gandhi M, et al. Improving women's diet quality preconceptionally and during gestation: effects on birth weight and prevalence of low birth weight--a randomized controlled efficacy trial in India (Mumbai Maternal Nutrition Project). American Journal of Clinical Nutrition. 2014;100(5):1257-1268.