CESAREAN-SECTION AND OPERATIVE VAGINAL DELIVERY IN LOW-RISK PRIMIPAROUS WOMEN, WESTERN-AUSTRALIA

Objectives. A major component of the increasing trend in cesarean sect ions in Western Australia is the rise in emergency cesarean sections i n primiparous women. The aim of this study was to identify independent risk factors (particularly those known early in pregnancy) associated with operative delivery in low-risk primiparous women. Methods. Retro spective multi-variate logistic regression analyses of antenatal and p erinatal data were conducted for all low-risk primiparous women enteri ng labor spontaneously and giving birth in Western Australia in 1987 ( n = 3641).Results. Of the subjects, 58% had a spontaneous vaginal deli very, 8% had an emergency cesarean section, and 34% had an operative v aginal delivery. The significant independent risk factors for emergenc y cesarean section were older maternal age, shorter maternal height, h eavier infant birthweight, and long labor. The risk factors for operat ive vaginal delivery were older maternal age, shorter maternal height, heavier infant birthweight, epidural anesthesia, labor/delivery compl ications, male infant, private patient status, and being married. Conc lusions. This multivariate analysis confirms known risk factors for op erative delivery in low-risk primiparous women and suggests that it ma y be possible to predict the likelihood of operative delivery for an i ndividual woman by using knowledge of maternal age and height and asse ssment of infant birthweight.