Effect of multivitamin supplements on weight gain during pregnancy among HIV-negative women in Tanzania.

Multivitamin supplementation has been shown to reduce the risk of low birthweight. This effect could be mediated through gestational weight gain. However, the effect of multivitamin supplementation on weight gain during pregnancy has not been fully studied. The objective of this study was to examine the effects of multivitamins on pregnancy weight gain. We enrolled 8468 HIV-negative women from Dar es Salaam, Tanzania, in a randomised, placebo-controlled trial of multivitamins on birth outcomes. Women were randomly assigned to receive either a daily oral dose of multivitamin tablets or a placebo and were weighed every 4 weeks from enrolment until the last visit before delivery. Intent-to-treat analyses were carried out to examine the effects of multivitamins on pregnancy weight gain. Multivariate linear and binomial regression models with the log-link function were used to examine the association of weight gain during pregnancy to birthweight. The overall total weight gain was 253 g (SE: 69, P: 0.0003) more, while the overall 4 weekly weight gain was 59 g greater (SE: 18, P: 0.005) among women who received multivitamins compared to placebo. Women in the lowest quartile of gestational weight gain had babies with an average birthweight of 3030 g (SD: 524), while women in the highest quartile had babies weighing 3246 g (SD: 486), on average. Prenatal multivitamin supplements increased gestational weight gain, which was a significant predictor of birthweight.

Macronutrient and sociodemographic determinants of gestational weight gain among HIV-negative women in Tanzania.

BACKGROUND: The effect of dietary macronutrient composition on the rate of gestational weight gain among women in sub-Saharan Africa is unclear. OBJECTIVE: To examine the effect of macronutrient intake on the rate of gestational weight gain among HIV-negative women in Tanzania. METHODS: The weights of 8,428 women were measured monthly from 12 weeks of gestation to term. Prenatal dietary intake was estimated as the cumulative average of multiple 24-hour dietary recalls. The association between energy intake and percentage of energy from carbohydrate, protein, and total fat and rate of weight gain (grams per month) was estimated from generalized estimating equation models. Macronutrient effects were adjusted for total energy using the nutrient density model and maternal age, maternal height, maternal mid-upper-arm circumference, parity, marital status, maternal occupation, maternal education, household wealth, season, and treatment regimen assignment. Body mass index (BMI) was considered as a confounder and a potential modifier of the effect of macronutrient intake on gestational weight gain. RESULTS: A 6 g/month increase in rate of weight gain was associated with every 100-kcal increment in daily total energy intake (95% CI, 1 to 12; p = .03). Analyses substituting 5% of energy from fat by protein showed that weight gain would decrease by 72 g/month (95% CI, 6 to 140; p = .03); substituting 5% of energy from carbohydrate by protein decreased gain by 70 g/month (95% CI, 15 to 124; p = .01). Baseline BMI did not modify these associations. CONCLUSIONS: Further research on the effects of macronutrient composition on gestational weight gain is needed to inform the design of supplementation programs for women in developing countries.