Associations of maternal pre-pregnancy body mass index with pregnancy complications and infant adiposity at 6 months corrected age: a two-center retrospective cohort study.

OBJECTIVE

To assess associations of maternal pre-pregnancy BMI with pregnancy complications, adverse perinatal outcomes, and infant adiposity at 6 months corrected age.

METHODS

This two-center retrospective cohort included 707 mother-infant dyads from 790 eligible pregnancies between March 2021 and June 2023. Pre-pregnancy BMI was classified as underweight (<18.5 kg/m2), normal-weight (18.5-23.9 kg/m2), overweight (24.0-27.9 kg/m2), and obesity (≥28.0 kg/m2). Infant anthropometry at 6 months corrected age was converted to WHO z-scores. Multivariable logistic regression was used to explore factors associated with adverse perinatal outcomes and infant obesity at 6 months corrected age.

RESULTS

Among 707 women, 47 (6.6%) were underweight, 314 (44.4%) normal-weight, 220 (31.1%) overweight, and 126 (17.8%) obese. Higher BMI category was associated with higher HbA1c, gestational diabetes mellitus, gestational hypertensive disorders, postpartum hemorrhage, macrosomia, NICU admission, and infant adiposity z-scores. Compared with normal weight, overweight (adjusted OR 1.38, 95% CI 1.01-1.90) and obesity (adjusted OR 1.86, 95% CI 1.24-2.78) were associated with higher odds of adverse perinatal outcomes. Maternal obesity was associated with higher odds of infant obesity at 6 months corrected age (adjusted OR 2.23, 95% CI 1.18-4.20), whereas breastfeeding was associated with lower odds (adjusted OR 0.65, 95% CI 0.39-0.94).

CONCLUSION

Maternal pre-pregnancy overweight and obesity were associated with pregnancy complications, adverse perinatal outcomes, and increased infant adiposity at 6 months corrected age. Preconception weight management and breastfeeding support may help reduce early metabolic risk.