Impact of maternal body mass index on the cesarean delivery rate in Germany from 1990 to 2012.

AIMS: Maternal obesity is a risk factor for cesarean delivery (CD). The aim of this analysis was to determine the association between early-pregnancy body mass index (BMI) and the rate of CD over the past two decades.
METHODS: We retrospectively analyzed data from the perinatal quality registry of singleton deliveries in the state of Hesse in Germany from 1990 to 2012. We divided the patients into groups according to the WHO criteria for BMI: underweight (<18.5), normal weight (18.5-<25), overweight (25-<30), obese class I (30-<35), obese class II (35-<40), and obese class III (≥40).
RESULTS: The analysis included 1,092,311 patients with available data regarding maternal BMI and mode of delivery. The CD rates for underweight (<18.5), normal weight (18.5-<25), overweight (25-<30), obese class I (30-<35), obese class II (35-<40), and obese class III (≥40) women increased from 14.4%, 16.1%, 19.5%, 22.3%, 25%, and 26.9% in the year 1990 to 27.9%, 31.4%, 38.8%, 45.1%, 50.2%, and 55.2% in the year 2012, respectively (P<0.001).
CONCLUSION: Maternal BMI in early pregnancy is linearly associated with the incidence of CD. We found a disproportionate increase of CD in morbidly obese women compared with the CD incidence in the reference BMI population over the past two decades.