Increasing Birth Weight above 4,000 Grams Is Associated with Adverse Outcomes among Births without Diabetes

This study aimed to evaluate the association of increasing birth weight above 4,000 grams and adverse obstetric outcomes and explore the influence of key maternal risk factors, including prepregnancy body mass index (BMI) and gestational weight gain (GWG), among births not complicated by diabetes.

This was a retrospective cohort study of singleton, non-anomalous, live births between 37 and 42 weeks' gestation in the United States between 2012 and 2021. Births complicated by diabetes or with birth weights less than 3,000 g were excluded. Births were stratified into four weight categories: 3,000 to 3,999 g (referent group), 4,000 to 4,499, 4,500 to 4,999, and ≥5,000 g. We performed stratified analyses by prepregnancy BMI and GWG per the National Academy of Medicine guideline recommendations. Analyses were performed via chi-square and adjusted incidence risk ratios for statistical comparisons.

There were 23,487,820 births included in this analysis. Higher birth weights were significantly associated with a higher risk of adverse perinatal outcomes, including cesarean delivery, blood transfusion, unplanned hysterectomy, maternal ICU admission, and obstetric anal sphincter injury. Additionally, the adjusted risk of all adverse neonatal outcomes also increased with increasing birth weight. When stratified by maternal risk factors, including BMI and GWG groups, we similarly found higher risk of adverse outcomes among higher birth weight categories, particularly among births complicated by maternal obesity or GWG above the National Academies of Medicine (NAM) recommendations.

Among births without diabetes, birth weights above 4,000 g were associated with an increasingly higher risk of adverse perinatal outcomes, and adverse outcomes remained higher even after stratification by BMI and GWG.

· Increasing birth weight is associated with higher rates of adverse outcomes.. · Perinatal outcomes by severity of macrosomia have not been thoroughly studied.. · Obesity and excessive weight gain in pregnancy is associated with adverse neonatal outcomes..