Adverse Childbirth and Perinatal Outcomes Among Healthy, Low-Risk Pregnant Women with Abnormal Total Gestational Weight Gain.

Little is known on the potential effects of abnormal gestational weight gain (GWG) among low-risk, healthy pregnant women with no comorbidities or gestational complications. We investigated perinatal outcomes of these pregnancies according to GWG as per the 2009 National Academy of Medicine (NAM) recommendations. A retrospective analysis of prospectively collected data of low-risk pregnant women giving birth at term between January 2016 and December 2020. Inclusion criteria were normal pregestational body mass index (pBMI) (18.5-24.9 kg/m) and no pregestational or gestational complication. Self-reported prepregnancy weight was used to calculate pBMI; GWG was the difference between maternal weight at childbirth and prepregnancy weight. Women were classified according to the 2009 NAM guidelines for GWG: insufficient (iGWG, <11.5 kg), adequate (aGWG, 11.5-16 kg), and excessive (eGWG, >16 kg). Logistic regression analysis with aGWG as referent was performed to independently estimate dose-response associations. During the study period, there were 4,127 (33.1%) births fulfilling the inclusion criteria. Fifty-two percent of women gained outside the recommended range: 33.5% had iGWG and 18.7% had eGWG. iGWG women were 40% more likely to have early-term births and small for gestational age neonates. In turn, eGWG women displayed increased odds of prolonged pregnancy (adjusted odds ratio [aOR] 1.32), cesarean section in labor (aOR 1.50), high-degree perineal tears (aOR 2.04), postpartum hemorrhage ≥1,000 mL (aOR 1.54), and large for gestational age newborns (aOR 1.83). Our data show that abnormal GWG independently associates with heightened risk of adverse outcomes among healthy, low-risk pregnant women with normal pBMI and no comorbidity or gestational complication.