Key takeaways:

• No significant differences were observed in gestational hypertension and preeclampsia rates.
• The findings highlight the need for individualized counseling for women who become pregnant after kidney donation.

Pregnancy for living kidney donors may be associated with increased risks for infants with low birth weight or small for gestational age, according to data published in Nephrology Dialysis Transplantation.

About 60% of living kidney donors internationally are women, many of whom are of reproductive age, according to Eva Carlsson, a researcher in the department of medical sciences at Uppsala University, Sweden, and colleagues. However, the association between living kidney donation and pregnancy outcomes has not been well-established in research, the researchers wrote.

Data derived from Carlsson E, et al. Nephrol Dial Transplant. 2026;doi:10.1093/ndt/gfag080.

“Our aim was to strengthen the evidence base for pre-donation counselling and clinical surveillance during post-donation,” Carlsson and colleagues wrote.

Using national registry data from Sweden, the researchers identified 679 women aged 45 years or younger who had a pregnancy before or after kidney donation between 1973 and 2022, accounting for 1,305 pre-donation and 139 post-donation pregnancies. Kidney donors who had a pregnancy were matched 1:10 to a control group of 1,390 nondonors who had a pregnancy.

The primary outcome was pregnancy-related hypertensive disorder, defined as gestational hypertension and preeclampsia. Secondary outcomes assessed low birth weight, small for gestational age delivery and placental dysfunction disorder (defined as a composite of preeclampsia and small for gestational age delivery), among others.

Results showed the incidences of gestational hypertension and preeclampsia were low between pre-donation, post-donation and matched control groups, according to the researchers.

Infants born after kidney donation, compared with the control group, were more likely to have low birth weight (OR = 2.69; 95% CI, 1.33-5.42) and be small for gestational age (OR = 2.54; 1.13-5.72).

In addition, odds of placental dysfunction disorder were greater among women with a post-donation pregnancy vs. women in the control group (OR = 2.08; 95% CI, 1.03-4.22).

Overall, the findings suggest that women with a post-donation pregnancy are more likely to face “modestly increased risks” for infants born small for gestational age and at low birth weight, but not for preeclampsia, according to the researchers.

“From a clinical perspective, pregnancy after kidney donation remains safe for most donors,” Carlsson and colleagues wrote. “While these findings do not warrant discouraging pregnancy after donation, they highlight the need for informed counselling and individualized antenatal monitoring, with close attention to both fetal growth and maternal hypertensive disorders.”