TOPLINE

About 53% of pregnancies involved weight gain above Institute of Medicine recommendations, and this excessive gain was associated with a higher risk for severe maternal morbidity (SMM) across all prepregnancy BMI categories.

METHODOLOGY

• Researchers conducted a retrospective cohort study to examine how gestational weight gain was associated with SMM.
• They used linked birth and hospital records in Ontario, Canada, and included more than 1 million singleton hospital deliveries at a gestational age of ≥ 20 weeks between 2012 and 2022.
• Researchers classified gestational weight gain as inadequate, adequate, or excessive using recommended ranges for specific prepregnancy BMI (adjusted for gestational age). They also analyzed mean weekly gain during the second and third trimesters.
• SMM during the delivery hospitalization was the primary outcome, defined as a composite of 13 relevant indicators.
• Prepregnancy BMI was classified as underweight, normal, overweight, and obesity classes I-III using World Health Organization cutoffs. Analyses were stratified by BMI and adjusted for key sociodemographic and clinical factors.

TAKEAWAY

• Gestational weight gain was excessive in 52.8% of pregnancies, adequate in 28.6%, and inadequate in 18.6%. SMM occurred at a rate of 14.59 per 1000 births.
• Pregnancies with excessive weight gain had a higher risk for SMM than those with adequate weight gain in every prepregnancy BMI category, with adjusted risk ratios (ARRs) between 1.16 and 1.33.
• Inadequate gestational weight gain was associated with a higher risk for SMM than adequate gain among individuals with normal weight (ARR, 1.13; 95% CI, 1.06-1.21) and overweight (ARR, 1.19; 95% CI, 1.05-1.35); no significant association was noted in the other BMI categories.
• Having a preexisting medical condition was associated with roughly twofold higher risk for SMM among those with adequate gestational weight gain. The combination of a preexisting condition plus inadequate or excessive gain was linked to the highest risk for SMM.

IN PRACTICE

"[The] findings support risk-stratified GWG [gestational weight gain] counseling that considers individual BMI subclass alongside medical comorbidities rather than categorical targets treating all individuals within a BMI class as equivalent," the researchers wrote.

SOURCE

The study was led by Sahar Khademioore, MSc, of McMaster University in Hamilton, Ontario, Canada. It was published online on October 22 in JAMA Network Open.

LIMITATIONS

SMM was recorded only during the delivery hospital stay; thus, cases before or after that admission may have been missed. Many individual SMM conditions were uncommon, and researchers combined 13 conditions with possibly different mechanisms into a composite outcome. Few events occurred in individuals with obesity classes II and III.

DISCLOSURES

The study received support from the Juravinski Research Institute, in collaboration with other organizations as part of the SERENE project. One author reported receiving personal fees and grants from multiple companies outside the submitted work. Another author reported receiving grant support from the Canadian Institutes of Health Research.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.