Objective: To examine if a "dose-response" relation exists between different classes of pre-gravid obesity and selected perinatal outcomes.
Methods: We evaluated 16,566 obese mothers, including 12,064 (72.8%), 3410 (20.6%), and 1092 (6.6%) with obesity class I, II, and III, respectively. We compared maternal age, primiparity, gestational age at birth, birth weight, GDM, hypertensive disorders, and the incidence of cesarean sections.
Results: There was a significantly increased incidence (from class I to class III) for GDM (8.5-14.4%), chronic hypertension (2.8-9.0%), gestational hypertension (6.7-14.2%), and for preeclampsia (5.3-9.3%). No such relationship existed for birth weight and gestational duration.
Conclusion: Classes of obesity during pregnancy exhibit a "dose-response" relationship with maternal morbidity, but no such relationship was found with pregnancy duration and birth weight.
Keywords: Gestational diabetes; Hypertension; Obesity; Pregnancy outcomes.