Pregnancy outcome in women who have an organ transplant is no worse after they undergo the procedure than it is before they have the surgery, results from a large Swedish population study have found.
“The outcome data in the present study agree well with what is known in the literature: a very high rate of preterm birth, of low birth weight, and of small for gestational age,” reported the investigators, who were led by Bengt Källén, M.D., of the Tornblad Institute, University of Lund, Sweden.
“The advantage of the present study is that it represents a total population and that the outcome data were obtained from a medical birth register, based on original medical record data,” they said (Br. J. Obstet. Gynaecol. 2005;112:904–9).
Using Sweden's hospital discharge register, the investigators identified women who had an organ transplant during 1973–2002. Their deliveries before and after transplantation were identified from the country's medical birth register over that same period.
A total of 976 deliveries occurred before organ transplantation and 149 after the procedure, which represented only about half the expected number of deliveries, after the researchers adjusted for year of delivery and maternal age.
No statistically significant differences in the odds of having a miscarriage before transplantation vs. after transplantation were seen (odds ratios of 2.2 vs. 3.2, respectively).
High rates of preeclampsia (22% following kidney transplantation and 33% for liver transplantation), preterm birth (46%), low-birth-weight (41%), and small-for-gestational-age babies (17%) were found for deliveries after transplantation, but similar frequencies were found among deliveries that occurred a few years before transplantation.
A congenital malformation was identified in 5.8% of infants born before organ transplantation and in 6.7% of those born after organ transplantation, but the two rates did not differ.
The authors pointed out that “among the 15 infants born after maternal liver transplantation, there were two with a congenital malformation, one of which was complex and serious: esophageal atresia with a heart defect and an iris malformation. This woman was the only one who had been treated with MMF [mycophenolate mofetil]. This may be a coincidence. Only few pregnancies exposed to MMF are published in the literature.”
Dr. Källén and colleagues reported that the major reason for the overall pregnancy outcomes observed in the study stems from disease morbidity, not from the transplantation itself.
In addition, the investigators found “no clear-cut effect” of fetal exposure to immunosuppressive drugs on increased morbidity in later life. Studies with longer follow-up are needed, they added.