Grant: CIHR New Investigator

One in 3 women in BC delivers her first child by cesarean birth. Most of these women (80%) have a cesarean delivery in later pregnancies as well ('elective repeat' cesareans). It is currently recommended that elective repeat cesarean deliveries be done when the mother is at least 39 weeks pregnant, because the baby may have breathing complications if it's delivered before this age. It is therefore concerning that despite the risks to the baby, most elective repeat cesarean deliveries (62%) in BC seem to be happening before 39 weeks. The goal of this research is to better understand current practice in timing of elective repeat cesarean deliveries, and how the age of delivery may affect the health of the mother and baby. Using electronic medical records in the BC Perinatal Database from all women who had an elective repeat cesarean delivery in BC between 2001 and 2010, we will first try to better understand what factors are causing the high rate of early term delivery. For example, is a woman having her cesarean in a smaller hospital more likely to be delivered before 39 weeks than a women having her cesarean at a larger hospital? Finally, there is a concern that planning the surgery for after 39 weeks makes it more likely that the mother will go into spontaneous labour before her scheduled surgery, which may increase the risk of complications for the mother. We will therefore also calculate the week-by-week risks for both mother and baby in order to identify the time in pregnancy at which both risks are lowest. 'Elective repeat cesarean' is currently the most common reason for a cesarean delivery, so the time in pregnancy at which the surgery is done is an issue for a large group of pregnant women. The results of this study will help to make sure that elective repeat cesarean deliveries in Canada are done at the week of pregnancy that leads to the best outcomes possible for both mother and baby.