This study aimed to investigate the association between weight loss in obese pregnant women and relevant maternal and neonatal outcomes. In the total population, 854 (4.7%) obese pregnant women reported weight loss. Weight loss and low weight gain were related to a recuced incidence of gestational hypertension for women with class I obesity (greater weight loss adjusted odds ratio [OR] 0.31, 95% confidence interval [CI] 0.11-0.84; lesser weight loss adjusted OR 0.46 95% CI 0.21-0.99; low gain adjusted OR 0.71 95% CI 0.54-0.93), a reduction in the rate of emergency cesarean delivery, but only in those with class II obesity (greater weight loss adjusted OR 0.24, 95% CI 0.07-0.78; lesser weight loss adjusted OR 0.50, 95% CI 0.26-0.97; low gain adjusted OR 0.55, 95% CI 0.38-0.79), and decreased macrosomia and large-for-gestational-age neonates in women in all classes of obesity, with the highest decrease for women with class III obesity (greater weight loss adjusted OR 0.15, 95% CI 0.05-0.49; lesser weight loss adjusted OR 0.37, 95% CI 0.15-0.90 for macrosomia). No association between weight loss and low birth weight, small-for-gestational-age neonates, or admission to the neonatal intensive care unit was found in the different obesity classes.
Weight loss in obese pregnant women was related to decreased perinatal risks but not with the rate of low birth weight or small-for-gestational-age neonates in obese women from class III in this affluent region. Stratification of recommended gestational weight gain ranges in obese women should be considered.d