Incidence and determinants of low birth weight in Peninsular Malaysia: A multicentre prospective cohort study

Pregnant mothers are at risk of many adverse pregnancy outcomes, including infants with low birth weight (LBW). The World Health Organization aimed to achieve a 30% reduction in the number of LBW infants by the year 2025. In this study, we aimed to determine the incidence and determinants of LBW infants among pregnant mothers attending government health clinics in Peninsular Malaysia.

A prospective cohort study "Relative Risk of Determinants of Adverse Pregnancy Outcomes Among Pregnant Mothers Attending Government Health Clinics, Peninsular Malaysia, PEN-MUM" was conducted from March 2022 until March 2023 at 20 government health clinics in Peninsular Malaysia that were randomly selected through a multistage sampling method. Malaysian pregnant mothers between 18 and 49 years old were recruited at 12-18 weeks of gestation and followed up at three time points: 1 (24-28 weeks of gestation), 2 (36-40 weeks of gestation), and 3 (post-delivery). Eight exposure factors of LBW were studied: gestational weight gain, dengue infection, urinary tract infection, COVID-19 infection, gestational hypertension, preeclampsia, maternal anemia, and gestational diabetes mellitus (GDM).

Among 507 participants enrolled in the cohort, 40 were lost to follow-up. A total of 467 were included in the final analysis, giving an attrition rate of 7.9%. The incidence of LBW infants in Peninsular Malaysia was 14.3%. After adjusting for three covariates (ethnicity, employment status, and gestational age at birth), three determinants of LBW were identified. The risk of giving birth to LBW infants was higher among those with inadequate gestational weight gain (aRR = 2.86, 95% CI: 1.12, 7.37, p = 0.03), gestational hypertension (aRR = 4.12; 95% CI: 1.66, 10.43; p = 0.002), and GDM (aRR = 2.21; 95% CI: 1.18, 4.14; p = 0.013) during the second and third trimesters.

The incidence of LBW infants in Peninsular Malaysia can be considered high. Having inadequate gestational weight gain, gestational hypertension, and GDM in the second and third trimesters increased the risk of LBW infants by threefold, fivefold, and twofold respectively. Thus, intervention strategies should target prevention, early detection, and treatment of gestational hypertension and GDM, as well as promoting adequate weight gain during antenatal care.