Impact of Low Maternal Weight on Pregnancy and Neonatal Outcomes.

Chahal, Nikhita; Qureshi, Tanya; Eljamri, Soukaina; Catov, Janet M; Fazeli, Pouneh K

Objective To examine the effect of underweight maternal body mass index (BMI) on pregnancy complications and neonatal outcomes. Design Cohort study. Setting Tertiary academic center. Patients A total of 16 361 mothers who delivered a singleton between 2015-2021 with either a BMI <18.5 kg/m2 (n = 732) or normal BMI (18.5 ≥ BMI <23 or 25 kg/m2, n = 15 629) at the initial prenatal visit or within 6 months of the initial visit. Main Outcome Measures Birthweight, gestational age, neonatal intensive care unit admission, preterm birth, and fetal death; obstetrical complications including preeclampsia/eclampsia, premature rupture of membranes, preterm premature rupture of membranes, and postpartum hemorrhage. Results Underweight women were younger and less likely to have private insurance (P <.01 for both) than normal-weight women. Approximately 23% of infants born to underweight mothers were small for gestational age and 15% were low birth weight vs 13.5% and 9% of infants of normal-weight mothers, respectively (P <.01 for both). These differences remained significant after adjusting for potential confounders. In adjusted logistic regression models, underweight women had a decreased risk of premature rupture of membranes and postpartum hemorrhage compared to normal-weight women. Conclusion Underweight BMI during pregnancy is associated with an increased risk of small for gestational age and low birth weight infants and a decreased risk of premature rupture of membranes and postpartum hemorrhage. These findings suggest underweight BMI during pregnancy increases the risk of adverse neonatal outcomes, while maternal-related pregnancy outcomes are less affected.

LOW birth weight; PREMATURE rupture of fetal membranes; SMALL for gestational age; NEONATAL intensive care units; PREGNANCY complications

Journal of the Endocrine Society, 2025, Vol 9, Issue 1, p1

2472-1972

Academic Journal

10.1210/jendso/bvae206