Women who have delivered a prior baby by Cesarean section may face an increased risk of dying or experiencing complications during vaginal births in the future, according to the findings of a new study.
Researchers with the Canadian Perinatal Surveillance System found that while absolute rates of maternal morbidity and mortality were low, the complication risk was increased for women attempting vaginal births following a C-section. The findings were published May 7 in the Canadian Medical Association Journal (CMAJ).
The study compared maternal and infant outcomes for vaginal births after c-section delivery versus elective repeat c-sections. They used data on nearly 200,000 women from the Discharge Abstract Database that includes all hospital deliveries in Canada, excluding Quebec. The study included women between 37 and 43 weeks gestation and who had a single prior c-section delivery between April 2003 and March 2015.
The data indicated overall rates of maternal death were low. However, they were significantly higher for women and their newborns who attempted vaginal birth after c-section, compared with elective repeat c-section delivery.
Complications during vaginal births were also higher for those mothers and infants whose mother had a c-section during prior delivery. While the findings of the new study indicated the overall risk of complication for any one woman was also still low, those mothers still faced an increased risk.
The number of women with prior c-section delivery increased during the study period. However, the rate of women who underwent or attempted vaginal delivery after c-section remained about the same.
The outcomes for infants worsened during the study period, according to the findings. When a baby was delivered vaginally to a mother who had a prior c-section during a prior delivery, there were higher rates of complications.
Those infants had an increased risk of death as well. Researchers said they were surprised by these findings and further studies are needed to help explain the results.
However, it is not the first time c-sections have been linked to risks of complications in pregnancy. Previous research has also indicated c-sections may pose complication risks. One study indicated women who undergo c-sections face a higher risk of miscarriages and stillbirths in later pregnancies.
Researchers said that the findings highlight the need for patient screening for those who want to attempt a vaginal delivery after having a prior c-section. Labor and delivery should also be carefully monitored in these cases to reduce the risk to both the mother and infant.
Researchers emphasized that both delivery methods are safe and reasonable options for women in general. However, the delivery method should be chosen based on the woman’s desire for a vaginal delivery, absolute risk, and other health factors.