Background: For young women who require cardiac valve replacement, the optimum prosthetic type for successful future pregnancy is not well established. Current data is limited to single-center studies and guidelines offer weak or no recommendations on valve selection. This study compares outcomes of pregnancy in women with mechanical valves (MHVs), bioprosthetic valves (BHVs), and valve repair.
Methods: This was a retrospective analysis of 268 pregnancies in 222 women with a history of cardiac valve replacement or repair in California and New Jersey between 2005 and 2015. Each pregnancy was treated as a unique event. Patients were identified using state-run mandatory administrative databases which capture all inpatient, emergency department, and ambulatory surgery discharges. A multivariable logistic regression model with clustering by patient was used to identify factors associated with pregnancy loss, defined as spontaneous or induced abortion, fetal death, or maternal death prior to delivery. Covariates included maternal demographic characteristics and baseline comorbidities, time between most recent valve operation and pregnancy, year of pregnancy, and valve characteristics.
Results: There were 64 pregnancies with MHVs present, 107 with BHVs, and 97 with repair only. Mean age at the time of first valve operation was 27.5 years (SD, 7.9 years; range, 11.2-53.7 years). Mean maternal age was 30.3 years (SD, 6.4 years; range, 15.6-54.9), with no significant difference between the three groups. Rates of spontaneous abortion for MHVs, BHVs, and repair were 32.8%, 8.4%, and 13.4%, respectively (p<0.0001), and rates of total pregnancy loss were 57.8%, 15.0%, and 22.7% (p<0.0001). After adjustment for covariates, the odds ratio for pregnancy loss with MHVs compared to BHVs was 5.3 (95% CI, 3.9-28.3) and 1.2 (95% CI, 0.9-6.2) with repair compared to BHVs. Other risk factors for pregnancy loss included maternal age ≥35 years and maternal hypertension.
Conclusion: For women in the United States with mechanical heart valves, the risk of pregnancy loss is significant, with less than half of all pregnancies successfully progressing to delivery.