Gestational weight gain and obstetric outcomes in women with obesity in an inner-city population.

Objectives: To describe maternal and perinatal outcomes in patients with BMI ≥30 kg/m by BMI class and gestational weight gain.

Methods: Retrospective review of singleton pregnancies with pre-pregnancy BMI ≥30 kg/m who received care at our institution between January 1, 2016 and December 31, 2021. Patients were divided into three categories based on BMI (kg/m): Class I (BMI 30.0-34.9), Class II (BMI 35-39.9), and Class III (BMI≥40) obesity. For gestational weight gain analysis, pregnancies were stratified into three groups: <11 pounds, 11-20 pounds, and >20 pounds. Maternal demographics and outcomes were compared using chi-square analysis, analysis of variance, nonparametric tests, and multivariable regression analysis.

Results: Of 641 patients included, 299 (46.6 %) were in Class I, 209 (32.6 %) in Class II, and 133 (20.7 %) in Class III. Readmission within 6 weeks postpartum, the only outcome found to have a significant difference between BMI categories, was higher in the Class III group (p=0.01). One hundred sixty-two (25.3 %) patients gained <11 pounds, 164 (25.6 %) gained 11-20 pounds, and 313 (48.8 %) gained ≥20 pounds. Greater gestational weight gain was associated with increased rates of cesarean delivery (p<0.001), higher quantitative blood loss (p=0.006), longer length of hospitalization (p=0.03), and higher birthweights (p<0.001).

Conclusions: This represents a unique and actionable opportunity for clinicians to counsel and support their patients in adhering to optimal weight gain targets throughout their pregnancy. Future studies are needed to determine the optimal gestational weight gain recommendations for obese patients.