Optimal timing of delivery for high risk pregnancies

Early delivery (delivery before spontaneous labour by induced labour or caesarean birth) is often considered for high-risk pregnancies to prevent stillbirths and protect the mother from developing pregnancy complications. However, the optimal time for early delivery is often unclear. Although birth between 37 and 41 weeks of pregnancy was once considered ideal, babies delivered early at 37 to 38 weeks are more likely to have breathing complications than babies delivered later. Deciding when a higher-risk pregnancy should be delivered therefore involves balancing the risks to the baby from delivering too early against the risks to the mother and fetus from delaying delivery too long.

Dr. Jennifer Hutcheon's research focuses on better understanding the risks and benefits associated with early delivery and how they change on a week-by-week basis. She is studying the optimal timing of delivery for repeat caesarean surgeries (a caesarean scheduled after the caesarean delivery of a previous child). Delivery before 39 weeks is not recommended because it will increase the risk of breathing complications in the infant at birth. However, planning the surgery for a later week of pregnancy makes it more likely that the mother will go into spontaneous labour before her scheduled surgery. Early work has found that despite the risks to the baby, 62% of repeat caesarean births in British Columbia happen before 39 weeks.

Dr. Hutcheon will review the medical records from all pregnancies in BC between 2001 and 2010 stored in the BC Perinatal Database Registry to better understand the factors causing the high rate of early-term delivery in women having repeat caesareans and the potential risks associated with delaying delivery until 39 weeks or later. Using large population and clinical databases, she will also examine the week-by-week risks of delivery and delaying delivery in other higher-risk populations, such as twin pregnancies and older mothers.

Dr. Hutcheon will use the information she obtains to calculate the week-by-week risks for mother and infant associated with delivery and with delaying delivery, in order to highlight the time in pregnancy at which both risks are lowest. She anticipates that her work will help inform best practice in the province and will ultimately have a positive influence on the health of babies born in BC.