Cardiovascular complications following cesarean section and vaginal delivery: a national population-based study

Rates of cesarean section are rising in both developed and developing countries and while pregnancy and cesarean section are established as risk factors for thromboembolism and stroke, large population-based investigations focusing on all types of cardiovascular complication after delivery is missing. The aim was to analyze the risk of severe cardiovascular complications in the post-partum period following delivery by cesarean section. We also had a control group of vaginal deliveries and a reference group with nulliparas.

This Swedish population-based study used three national registers between 2005 and 2017 and comprised a total of 1 165 684 individuals. Unselected register data was cross-linked and cardiovascular adverse events were identified by ICD diagnosis codes. 140 128 women (209 391 deliveries) were included in the cesarean group and 614 355 women (973 429 deliveries) in the vaginal control group. The reference group comprised 411 201 age-matched nulliparous women. The primary analysis was the risk of severe cardiovascular complications within 42 days of cesarean section or vaginal delivery. The secondary analysis evaluated risk factors for cardiovascular complications.

In the cesarean section group, 410 (0.20%) had a serious cardiovascular event within 42 days after delivery, and in the vaginal control group the number was 857 (0.09%). The risk of having an adverse cardiovascular event was significantly greater in the cesarean group (OR 2.23, CI 1.98 to 2.51) for all types of cardiovascular events. Risk factors were high BMI, preeclampsia, greater maternal age, tobacco use and acute cesarean delivery.

The absolute numbers on severe maternal morbidity after delivery are low. However, since almost half of the world's population are affected and the frequency of elective cesarean section continues to rise, a doubling of the risk for a severe cardiovascular event within 42 days of delivery is important to consider globally.