Purpose: 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. Materials and Methods: 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/m2) 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. Results: 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). Conclusion: 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.
Keywords: childbirth; gestational weight gain; low risk; outcomes.