Abstract 2966: Cumulative Pregnancies Increase Risk of Cardiac Transplant Rejection Requiring Treatment: An Analysis of the United Network for Organ Sharing Database
Background: Rejection is a major cause of morbidity and mortality following orthotopic heart transplantation (OHT). Prior investigation suggests that females have a higher rate of rejection and that pre-transplant pregnancy is the driving factor; however, the incremental risk of each additional pregnancy is unknown.
Methods: We reviewed the United Network for Organ Sharing (UNOS) database to identify females who underwent OHT between 1988 and 2006 at age > 10 and for whom both prior pregnancy status and 1yr rejection status were known. These were stratified by number of pre-transplant pregnancies and by presence or absence of rejection requiring treatment within 1 yr after transplant.
Results: From 1988 to 2006, 10,063 females and 30,840 males underwent OHT. Of those, 3439 females met criteria and were included in the primary analysis. Rejection status was available for 11,777 males, who were separately compared with nulligravid females. The percentage of females with rejection at 1yr rose with each additional pregnancy (see graph: χ2 = 24.4 (p< 0.001); R2 = 0.959). 1yr rejection in females with no prior pregnancies reported was also significantly higher than 1yr rejection in males (49.5 (594/1201) vs. 45.1(5307/11777); χ2 = 8.5 (p < 0.005)).
Conclusions: We found, as previously described in smaller study populations, that female gender increases rejection risk. We also identified a direct correlation between number of pre-transplant pregnancies and risk of rejection requiring treatment within 1 yr. Further investigation is warranted to confirm that number of pregnancies is a risk factor for early rejection independent of age, use of induction therapy and PRA status.