Objectives: To compare several maternal-fetal morbidities comparing the Institute of Medicine IOM 2009 recommendations (IOMR: 5-9 kg in all obese women) between women with adequate gestational weight gain (GWG) and Inadequate (less than 5 kg), and excessive those gaining more than 9 kg among obese women class I (30-34.9 kg/m2) and class II (35-39.9 kg/m2).
Study design: South-Reunion University's maternity (Reunion Island, Indian Ocean). 21-Year-observational cohort study (2001-2021). Epidemiological perinatal database with information on obstetrical and neonatal risk factors.
Main outcome measures: Cesarean sections, preeclampsia, means birthweight, rate of small (SGA) or large (LGA) for gestational age newborns and macrosomic babies (≥4 kg).
Results: Among the singleton term live births (37 weeks onward) we could define the pre-pregnancy body mass index and GWG in 85.9% of cases. The final study population focused on 10,296 obese women (7138 obesity class I - 30-34.9 kg/m2, 3158 obesity class II - 35-39.9 kg/m2). Concerning inadequate GWG (less than 5 kg), respectively for obese I and II, IOMR babies were heavier (plus 90 and 104 g, p < .001), were more prone to be LGA OR 1.61 and 1.69, p < .001, macrosomic OR 1.49 and 2.21, p < .0001, IOMR women had more cesarean sections OR 1.33, OR 1.45, p = .001, and for obese II a tendency for more term preeclampsia OR 1.83, p = .06.
Conclusion: This study demonstrates that for obese women these IOMR (5-9 kg) are mildly but significantly too high if we consider obesity class I and obviously too high for obesity class II (35-39.9 kg/m2).
Keywords: Pregnancy; cesarean section; epidemiology; gestational weight gain; obesity; pre-pregnancy body mass index; preeclampsia.