Effect of pre-pregnancy body mass index and weight gain during pregnancy on the risk of emergency cesarean section in nullipara

Abstract

We attempted to examine the effects of delivery via emergency cesarean section in nullipara, presenting with increase in body weight during pregnancy and pre-pregnant body mass index. A total of 1,024 nullipara with singleton pregnancy who experienced labor pain after 37 gestational weeks at St.Vincent's Hospital of Catholic University of Korea during 1 January 2004 to 31 March 2010 were enrolled in this study. Study patients were divided into four groups based on pre-gestational BMI, two groups based on weight gain more than 18 kg during pregnancy and three groups based on weight gain according to the guidelines of IOM (Institute of Medicine). Univariate and multivariate analysis were performed. On univariate analysis, the frequency of emergency cesarean section was increased both in pre-pregnant overweight women and women with excess weight gain during pregnancy. On multivariate analysis, however, increase in body weight during pregnancy according to IOM guidelines did not independently affect the frequency of emergency cesarean section. If the degree of increase in body weight during pregnancy was divided based on a definite numeric value of 18 kg, the frequency of cesarean section was significantly increased. For successful spontaneous delivery, the nullipara should become pregnant when the pre-gestational BMI is maintained at an appropriate level. We also propose that women should not gain more than 18 kg until delivery in all pre-BMI groups.