Obstetric and neonatal outcomes of extremely obese pregnant women after late preterm gestation.

Abstract

Objective: To determine the obstetric and neonatal outcomes of pregnant women with extreme obesity at birth after late preterm gestation.

Methods: This was a retrospective study on extremely obese pregnant women with body mass index (BMI) ≥ 40.0 kg/m² (obesity stage III according to the BMI classification of the World Health Organization) who had delivered at Seoul National University Bundang Hospital between September 2003 and February 2023. Fetal death in utero and preterm births before 34 weeks of gestation were excluded. Obstetric and neonatal outcomes were reviewed.

Results: A total of 94 extremely obese pregnant women were included and the median value of BMI at delivery was 42.4 kg/m². When analyzed according to the obesity II category of pre-pregnancy BMI, the rate of chronic hypertension was higher in the alleged extreme obese women than those with lower pre-pregnancy BMI (34% vs. 10%, p = 0.012). However, preterm labor with tocolytics was higher in the group with lower BMI than 35.0 kg/m² (26% vs. 5%, p = 0.007). The proportion of adverse neonatal outcomes such as neonatal intensive care unit admission, the use of respiratory support (including positive pressure ventilation, continuous positive airway pressure, and mechanical ventilator), and jaundice were higher in the group with pre-pregnancy BMI < 35.0 kg/m² than that with BMI ≥ 35.0 kg/m² group (all p-value < 0.05). The use of neonatal respiratory support increased as the category of pre-pregnancy BMI was lower and as the degree of weight gain during pregnancy was higher.

Conclusions: In extremely obese women (stage III) at delivery in late preterm gestation, the obstetric outcomes such as use of tocolytics for preterm labor and adverse neonatal respiratory outcomes seemed to be higher for the women who were not that much obese before pregnancy than those who were already extremely obese. Therefore, weight gain during pregnancy needs to be closely monitored for pregnant women especially when obese.