MacDorman, M. F., Declercq, E., Menacker, F., & Malloy, M. H. (2006). Birth, 33, 175-182.
The incidence of cesarean births without medical or obstetric indications has been increasing in the United States, and some of this increase has been attributed to maternal request for cesarean birth (National Institutes of Health [NIH], 2006). The purpose of this population-based study was to examine neonatal mortality risks associated with primary cesarean section compared to vaginal birth for women with "no indicated risk," defined as having a full-term singleton infant in vertex presentation, with no medical risk factors or complications of labor and/or delivery reported on the birth certificate. The investigators analyzed national linked birth and infant death data for the 1998-2001 birth cohort in the United States. Neonatal mortality rates were higher among infants delivered by cesarean birth (1.77 per 1,000 live births) compared to infants delivered vaginally (0.62). After adjusting for maternal age, race/ethnicity, parity, education, period of gestation, and infant birth weight, women having a cesarean birth were at least two times more likely to have a neonatal death than women with a vaginal birth, even when deaths due to congenital anomalies and Apgar scores less than 4 were excluded. Overall, the neonatal mortality rate for vaginal and primary cesarean births in this low-risk population was very low; however, the results suggest a higher risk of neonatal death associated with cesarean birth. Our own work in Canada suggests that planned cesarean delivery poses higher risks of several severe maternal morbidities compared with planned vaginal delivery (Liu et al., in press). Although many factors enter into a woman's decision to request a cesarean birth, healthcare professionals should keep apprised of evidence about the benefits and risks of planned cesarean delivery compared to planned vaginal delivery in order to assist women in making an informed decision. Much more research is needed in this area. Meanwhile, readers are referred to the NIH document for a review of current evidence.
Maureen Heaman
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