Kidney Donors at Increased Risk of Gestational Hypertension and Pre-Eclampsia

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Women who become living kidney donors are at increased risk of gestational hypertension and pre-eclampsia, suggests a study in the New England Journal of Medicine.

The retrospective cohort analysis included 85 women in Ontario who donated a kidney between 1992 and 2010 and subsequently become pregnant. The median age at donation was 29 years; the women had a total of 131 pregnancies after entering the cohort.

They were matched to 510 healthy nondonors for age, year, urban versus rural residency, income, number of pregnancies, and time to first pregnancy. The control women had a total of 788 pregnancies. The rates of hospital-diagnosed gestational hypertension or pre-eclampsia were compared for donors versus nondonors, along with other maternal and fetal outcomes.

The primary outcome of gestational hypertension or pre-eclampsia was more than twice as frequent among women who donated a kidney: 11 percent versus 5 percent of pregnancies: odds ratio 2.4. The odds ratios for the individual outcomes were 2.5 and 2.4, respectively.

Other maternal and fetal outcomes were similar between groups, including preterm birth and low birth weight. There were no cases of maternal death, stillbirth, or neonatal death among the donors.

Young women who are considering living kidney donation commonly ask about the possible effects on future pregnancies. Some studies have reported an increased risk of gestational hypertension and pre-eclampsia after donation, but these findings have been controversial.

The new study finds a significantly increased risk of gestational hypertension or pre-eclampsia in pregnancies occurring in woman after living kidney donation compared with similarly healthy nondonors. The authors believe that this information should be included in clinical practice guidelines and shared in the informed consent process. They note that most women in their donor cohort had uncomplicated pregnancies after donation [Garg AX, et al. Gestational hypertension and preeclampsia in living kidney donors. N Engl J Med 2015; 372:124–133].