Results of prior sirolimus series reports have been confounded by concomitant mycophenolate exposure. The purpose of this study was to describe pregnancy outcomes with exposure to sirolimus without mycophenolate exposure. Data were collected by the National Transplantation Pregnancy Registry (NTPR) via questionnaires, phone interview and hospital records. Of these, there were 19 transplant recipients (13 kidney (K), 3 liver (L), 2 heart, and 1 pancreas-kidney (PK)) reporting 22 pregnancies resulting in 24 outcomes with exposure to sirolimus during pregnancy without concomitant exposure to mycophenolic acid products. Sirolimus was continued throughout 11 pregnancies, discontinued (n=4) or switched (n=7) to another immunosuppressive agent during pregnancy. Only 6 pregnancies were reported as being planned. Additional immunosuppression during pregnancy included tacrolimus (n=12), cyclosporine (n= 6) and azathioprine (n=2). Initial immunosuppression in the other 2 recipients consisted of sirolimus and prednisone. There were no rejections during pregnancy. There were 18 live births, 5 miscarriages and 1 termination of pregnancy. There were 2 birth defects reported among the live births, one infant had Tetralogy of Fallot and the other had vermian hypoplasia of the cerebellum (diagnosed as a mild Dandy-Walker variant). None of the offspring were breastfed while their mothers were taking sirolimus. At last follow-up, all children were reported healthy and developing well. Among the mothers, 3 K recipients lost graft function at 0.34, 1.45 (recipient died), and 2.5 yrs postpartum, and 1 KP recipient lost her P transplant 4 yrs postpartum. There were no graft losses in the heart or liver recipients.

Conclusions: Successful pregnancy outcomes with exposure to sirolimus have been reported in various transplant recipients. Sirolimus exposure without mycophenolate during pregnancy does not appear to be associated with an increased risk or a pattern of birth defects. Given the small population herein reported, additional entries to the NTPR will assist in formulating stronger conclusions regarding sirolimus use during pregnancy.

« Back to 2015 American Transplant Congress