Maternal Weight Gain During the Third Trimester as a Risk Factor for Low Birth Weight: A Case–Control Study in Solok, West Sumatera

Abstract

Background: Low birth weight (LBW) remains a significant public health concern, contributing to increased neonatal morbidity and mortality. Maternal nutritional status and gestational weight gain are key determinants of fetal growth. This study aimed to analyze the relationship between maternal weight gain during the third trimester and the incidence of low birth weight among pregnant women in Solok, West Sumatera.

Methods: This analytical observational study employed a retrospective case–control design. The study involved 78 respondents consisting of 26 mothers who delivered LBW infants (<2500 g) and 52 mothers who delivered normal-birth-weight infants (≥2500 g). Data on maternal weight gain were collected from maternal and child health records (KIA books) and analyzed using the Spearman correlation test. Statistical significance was set at p < 0.05.

Results: The median maternal weight gain during the third trimester was 4 kg (range: 3–6 kg) in the case group and 7 kg (range: 4–11 kg) in the control group. A significant positive correlation was found between maternal weight gain and infant birth weight in both the case group (r = 0.625; p = 0.001) and the control group (r = 0.325; p = 0.019). These findings indicate that greater maternal weight gain during the third trimester is associated with higher infant birth weight.

Conclusion: Maternal weight gain during the third trimester plays a crucial role in determining infant birth weight. Adequate gestational weight gain reflects sufficient maternal nutrient intake, which supports optimal fetal growth and reduces the risk of LBW. Strengthening maternal nutrition programs and regular antenatal monitoring are essential strategies to improve pregnancy outcomes and lower the incidence of LBW.

Keywords: Low Birth Weight, Maternal Weight Gain, Pregnancy, Solok, Third Trimester