Effects of pre-pregnancy maternal underweight on pregnancy and perinatal outcomes of the foetus

Background: Maternal underweight, defined as a body mass index (BMI) less than 18.5 kg/m², poses significant challenges in maternal and fetal health. Despite being prevalent worldwide, particularly in low- and middle-income countries, the effects of pre-pregnancy underweight on pregnancy and perinatal outcomes remain under-researched compared to maternal obesity. This study aims to explore the complex interactions between pre-pregnancy maternal underweight and adverse pregnancy outcomes such as low birth weight (LBW), preterm birth (PTB), and intrauterine growth restriction (IUGR), with a focus on Nigeria's diverse socioeconomic landscape. Materials and Methods: This study employed a retrospective analysis method, leveraging data from national health surveys, birth registries, and healthcare databases across six Nigerian states (Lagos, Osun, Anambra, Imo, Kano, and Kaduna). The study examined pre-pregnancy BMI, maternal demographics, socioeconomic factors, and pregnancy outcomes. The analysis included the systematisation setback technique to assess the relationship between pre-pregnancy underweight and pregnancy outcomes, considering regional nutritional disparities. Results: The findings indicated a significant association between maternal underweight before pregnancy and adverse pregnancy outcomes. Underweight mothers were more likely to experience LBW, PTB, and SGA infants. Socioeconomic and demographic factors, such as low educational attainment and rural residence, were identified as significant predictors of maternal underweight. The study highlighted regional differences, with higher rates of underweight mothers in economically disadvantaged areas. Conclusion: Addressing pre-pregnancy maternal underweight is crucial for improving perinatal outcomes. The study underscores the need for targeted public health interventions, including nutritional support, education, and enhanced healthcare access, particularly in low-resource settings. By mitigating the risks associated with maternal underweight, healthcare professionals can promote healthier pregnancies and better developmental trajectories for infants.