Limited data exist to characterize maternal and fetal outcomes during pregnancy undergoing cardiac operations using cardiopulmonary bypass.

A retrospective review was performed of all pregnant individuals who underwent cardiac surgery using cardiopulmonary bypass at a single center from 1978 to 2023. Descriptive statistical analysis was performed, with a median reported for continuous variables and incidence for dichotomous variables.

Twenty-nine pregnant patients with a median age of 28 years (interquartile range [IQR], 25-32 years) years underwent cardiac surgery using cardiopulmonary bypass at a median gestation of 25 weeks (IQR, 16-29 weeks). Surgery was performed in the first trimester for 3 patients (10%), second trimester for 16 (55%), and third trimester for 10 (35%). Procedures were emergent in 15 (52%) and urgent in 14 (48%). There was 1 (3%) maternal death 2 days after mechanical aortic valve thrombectomy and 5 (17%) fetal losses. Fourteen patients who underwent cardiac surgery using cardiopulmonary bypass with continuing pregnancy experienced a 29% fetal mortality rate, and 7 patients underwent delivery before surgery and experienced 14% fetal mortality. Among cases of fetal loss, surgery was performed at a median of 25 weeks (IQR, 21-26 weeks) compared with a median of 23 weeks (IQR, 20-29 weeks) in cases without fetal loss (P = .55).

Cardiac surgery during pregnancy was associated with low maternal mortality but significant fetal mortality. This single-institution series supports consideration of cesarean delivery before cardiopulmonary bypass procedures if the fetus is of a viable gestational age to minimize mortality.