PHILADELPHIA – Women who become pregnant after receiving a transplanted liver face an elevated risk of graft rejection, especially during or immediately following the pregnancy, based on a review of 161 U.S. cases.
"The data suggest poorer outcomes for both mothers and their newborns in female liver recipients with risk factors for graft loss within 5 years post pregnancy," Dr. Carlo B. Ramirez said at the American Transplant Congress. "The findings highlight the high-risk nature of this group, warranting closer follow-up of both mother and child," said Dr. Ramirez, a transplant surgeon at Thomas Jefferson University, Philadelphia.
Of the 161 women who became pregnant following a liver transplant and were enrolled in the National Transplantation Pregnancy Registry (in place since 1991), 16 (10%) lost their graft within 5 years following their first posttransplant pregnancy. The pregnancy and the 3 months following pregnancy posed a particular risk, with half of the women who eventually lost their graft experiencing rejection during that time. In a multivariate model that took into account baseline risk factors, women with a liver transplant faced a 14-fold increased risk for graft loss during the pregnancy, Dr. Ramirez said.
"A lot of patients who have a stable equilibrium with their graft may destabilize under stress. It is possible that there is low-grade, clinically insignificant rejection in some of these patients prior to pregnancy" that then becomes exacerbated by the stress of pregnancy, commented Dr. Jean C. Emond, professor of surgery and director of transplantation at Columbia University in New York. Dr. Emond suggested that a liver biopsy prior to pregnancy might be warranted to assess the stability of the transplant.
Other risk factors for graft loss included younger age of the mother and low gestational age at the time of delivery. In the multivariate analysis, the risk for graft loss fell by a statistically significant 26% for each additional year of age for the mother. Graft loss fell by a statistically significant 5% for each additional week of gestational age when delivery occurred.
Among the 16 women who lost their graft during pregnancy or the following 5 years, their average age when they conceived was 22 years old, compared with an average age of 28 years old among the 145 women who did not lose their graft. Average gestational age at delivery was 33 weeks among the women who lost their graft, and 37 weeks among the women who did not lose their graft.
The average age of the women at the time they received their liver transplant was 18 years among those who later lost their grafts, and 23 years among those who retained their grafts. However, the average time between transplantation and conception was an identical 4.3 years in both groups.
The only other risk factor for graft loss that approached statistical significance in the multivariate model was viral hepatitis as the etiologic agent for the liver failure that led to the transplants. Viral hepatitis was the cause of liver failure for six (38%) of the women who lost their grafts following pregnancy, and for 23 (16%) of the women who did not lose their grafts. In the multivariate model, viral hepatitis as the cause of liver failure was linked with a nearly fourfold increased risk for women losing their graft during or after pregnancy, but this relationship failed to meet the standard criterion for statistical significance, Dr. Ramirez said.
The congress was sponsored by the American Society of Transplant Surgeons. Dr. Ramirez said he had no disclosures. The National Transplantation Pregnancy Registry has been supported by grants from Novartis, Astellas, Genentech, Pfizer, Teva, and Sandoz.