A STUDY OF ASSOCIATION OF MATERNAL PRE-PREGNANCY LOW BMI WITH ADVERSE PREGNANCY OUTCOMES

Abstract

Background: Maternal nutritional condition prior to conception plays a critical role in determining pregnancy outcomes. A low body mass index (BMI) before pregnancy has been associated with unfavorable maternal and neonatal events; however, evidence evaluating the extent of risk across varying degrees of underweight remains limited in South Indian settings.

Materials and Methods: This prospective observational study was conducted over 12 months at Bhaarath Medical College and Hospital. A total of 120 antenatal women were enrolled, including 60 women with low BMI (<18.5 kg/m²) and 60 with normal BMI (18.5–24.9 kg/m²). Women with low BMI were further stratified into BMI <16, 16.1–16.9, and 17–18.4 kg/m² categories. Participants were followed from booking until delivery. Maternal characteristics along with antenatal, intrapartum, and neonatal outcome variables were systematically documented. Statistical evaluation was performed using the Chi-square test and Fisher’s exact test, trend analysis, and Pearson correlation as appropriate.

Results: Low BMI was associated with higher prevalence of anaemia, inadequate gestational weight gain, abnormal amniotic fluid indices, and non-reactive non-stress tests. Oligohydramnios was significantly more frequent in lower BMI categories, showing an inverse trend with increasing BMI. Neonates born to women with low BMI had lower mean birth weight and higher rates of low birth weight, intrauterine growth restriction, and neonatal hypoglycaemia. Maternal body mass index demonstrated a statistically significant positive association with neonatal birth weight, with the highest frequency of adverse outcomes observed among women in the lowest BMI category.

Conclusion: Reduced maternal pre-pregnancy BMI is linked to unfavorable antenatal and neonatal outcomes, with the magnitude of risk progressively rising as BMI declines. Stratifying underweight women may facilitate early identification and targeted nutritional interventions.