Obesity as an obstetric risk factor: does it matter in a perinatal center?

OBJECTIVES: Obesity before and during pregnancy is associated with several obstetrics risk factors for both mother and fetus. The aim of this retrospective study was to analyze the influence of BMI before pregnancy on distinct perinatal parameters. RESEARCH METHODS AND PROCEDURES: The study includes 5067 singleton pregnancies from 2001 to 2004 at the Department of Obstetrics and Gynecology, University of Leipzig. The study group was divided into BMI groups: <18.5, >or=18.5 to <25, >or=25 to <30, >or=30 to <35, >or=35 to <40, and >or=40 kg/m(2). Analysis of perinatal data included rate of intrauterine death, rate of cesarean section and shoulder dystocia, time of hospital stay for mother and newborn, and gestational age of delivery. Neonatal outcome variables included percentage of newborns weighing >4000 grams, rate of umbilical cord pH <7.10, and rate of 1-, 5-, and 10-minute Apgar scores of <8.
RESULTS: There was no difference in the gestational age at delivery among the groups. In the group with BMI >or=30 kg/m(2), the cesarean section rate was significantly elevated to 25.1%, with a more dramatic increase up to 30.2% in the group with BMI >or=35 kg/m(2) and 43.1% in the group with BMI >or=40 kg/m(2), mainly because of a higher number of secondary cesarean sections. Although newborns of obese women showed worse initial neonatal adaptation, the 10-minute Apgar values did not differ among the groups. The higher rate of operative deliveries and the trend to an increased rate of shoulder dystocia did not influence duration of the hospital stay for mothers and newborns or morbidity of both. DISCUSSION: A high pre-pregnancy BMI is clearly associated with a higher rate of cesarean section deliveries. However, under the compensating conditions of a tertiary perinatal center, overall morbidity of mothers and newborns seems not to be increased.