Gill, J. S. et al. The pregnancy rate and live birth rate in kidney transplant recipients. Am. J. Transplant. 9, 1541–1549 (2009).

Pregnancy rates in kidney transplant recipients are notably lower than those of the general population, an analysis of data from the United States Renal Data System (USRDS) reveals. Live birth rates in kidney transplant recipients are also much lower than previously estimated. “This suggests incomplete capture of failed pregnancies in the existing literature,” says lead researcher John Gill from the University of British Columbia, Vancouver.

The live birth rate was also lower than that reported from voluntary data sources...

Women with end-stage renal disease have a better chance of a successful pregnancy after kidney transplantation. Data on pregnancy outcomes are, however, limited. “Most of the existing information is derived from voluntary data sources that may be subject to bias,” Gill comments. His team, therefore, carried out a population-based study to assess pregnancy outcomes in kidney transplant recipients.

Data from the USRDS on 16,195 females (aged 15–45 years) who underwent kidney transplantation between 1990 and 2003 were analyzed. Gill explains that “this was done to permit ascertainment of all pregnancy events in these individuals while they maintained Medicare insurance.”

A total of 530 pregnancies were recorded in 483 women. The overall pregnancy rate in the study population was 33 per 1,000 females compared with more than 100 per 1,000 females per year between 1990 and 2000 in the general US population. Gill's team observed a dramatic drop in the pregnancy rate in renal transplant recipients from 59 per 1,000 in 1990 to 20 per 1,000 in 2000. This decline was more rapid than that reported in the general US population. “The live birth rate was also lower than that reported from voluntary data sources in the existing literature,” Gill noted.

“The reasons for [the low live birth rate] are unclear and require further study,” Gill comments, adding, “why the pregnancy rate declined over time should be pursued in future studies.”