Determinants of birth weight abnormalities at a university hospital in Mahajanga, Madagascar: a prospective case-control study

Background: Birth weight abnormalities, including low birth weight and macrosomia, represent a major public health problem due to their neonatal and long-term consequences. Identifying the associated factors helps guide prevention strategies adapted to the local context of the neonatology department of the University Hospital Center of Mahajanga, Madagascar. Methods: This was a prospective descriptive and analytical case-control study conducted from 19 March to 19 September 2024, in the neonatology department of the University Hospital Center of Mahajanga, Madagascar. Seventy-four newborns presenting with birth weight abnormalities were compared with 222 controls with normal birth weight. Sociodemographic, obstetric, and maternal factors were analyzed. Results: The hospital incidence of birth weight abnormalities was 9%. The identified risk factors were gestational hypertension (OR=9.84; 95% CI: 4.21–21.02), fewer than four antenatal care visits (OR=4.73; 95% CI: 2.01–10.12) and single marital status (OR=2.79; 95% CI: 0.98–7.99). Conversely, maternal age between 18 and 35 years (OR=0.42; 95% CI: 0.21–0.84), iron and folic acid supplementation (OR=0.34; 95% CI: 0.16–0.72), normal maternal body mass index (OR=0.51; 95% CI: 0.27–0.95) and secondary or higher education level also reduced the risk (OR=0.31; 95% CI: 0.15–0.66) had a protective effect. Conclusion: Birth weight abnormalities at the University Hospital of Mahajanga are mainly influenced by modifiable maternal determinants. Strengthening antenatal care and early management of hypertensive disorders could significantly reduce their frequency.