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Am J Perinatol 2026; 43(02): 172-179
DOI: 10.1055/a-2597-8542
Original Article

Association of Gestational Weight Gain with Adverse Pregnancy Outcomes in Individuals with Obesity

Authors

  • Kazuma Onishi 

    1   Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, Virginia
    2   Department of Reproductive Medicine, Asada Ladies Clinic, Nagoya, Aichi, Japan

  • Tetsuya Kawakita 

    1   Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, Virginia

Funding None.
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Abstract

Objective

This study aimed to determine optimal gestational weight gain (GWG) considering adverse infant and maternal outcomes among individuals with obesity, with detailed classification for body mass index (BMI) of 40 kg/m2 or higher.

Study Design

This study was a population-based retrospective cohort study, using U.S. birth certificate data from 2017 to 2021. We included nulliparous individuals with singleton pregnancies delivering live births between 370/7 and 416/7 weeks' gestation, excluding those with pregestational diabetes or hypertension, gestational diabetes, preeclampsia, major fetal anomalies, or chromosomal disorders. The study focused on three main outcomes: primary cesarean delivery, small for gestational age (SGA), and large for gestational age (LGA). GWG was evaluated in 2-kg increments, from weight loss >8 kg to gains ≥28 kg. Prepregnancy BMI was stratified into four categories: BMI of 30 to <35, 35 to <40, 40 to <50, and ≥50 kg/m2. Odds ratios and absolute risk reduction were used to identify GWG ranges with balanced risks for three outcomes within each BMI category.

Results

Among 1,677,968 individuals with obesity, increased GWG was associated with higher absolute risks of cesarean delivery and LGA and lower risk of SGA across all BMI categories. Optimal GWG ranges varied by prepregnancy BMI: >12 to ≤14 kg for BMI of 30 to <35 kg/m2; >10 to ≤12 kg for BMI of 35 to <40 kg/m2; >6 to ≤10 kg for BMI of 40 to <50 kg/m2; >0 to ≤8 kg for BMI of 50 kg/m2 or higher.

Conclusion

We identified higher upper and lower GWG limits for individuals with BMI of 30 to 50 kg/m2, and lower limits for those with BMI ≥50 kg/m2, compared with the guidelines recommended by the U.S. National Academy of Medicine. These findings suggest the need to tailor GWG recommendations based on the severity of obesity.

Key Points

  • Optimal GWG varies by obesity class, requiring tailored guidelines.

  • Those with BMI ≥50 kg/m may need lower target for gestational gain than current recommendation.

  • The optimal GWG range could be changed based on the outcomes of interest.

Keywords

cesarean delivery - intensive care unit - large for gestational age - neonatal death - neonatal intensive care unit - obesity - small for gestational age - weight loss

Supplementary Material



Publication History

Received: 26 December 2024

Accepted: 29 April 2025

Accepted Manuscript online:
01 May 2025

Article published online:
21 May 2025

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