Living Kidney Donation Linked to Modestly Higher Risk of Hypertensive Disorders in Pregnancy: JAMA

A new study published in the Journal of American Medical Association showed that women who donated a kidney experienced a slightly higher risk of developing hypertensive conditions in later pregnancies.

Individuals who conceive following a living kidney donation might face a heightened risk of complications related to pregnancy, although the data remains inconclusive. Thus, this research assessed whether pregnancies occurring after living kidney donation are linked to an elevated risk of negative pregnancy outcomes when compared to matched pregnancies in nondonors.

This matched cohort study utilized provincial administrative health care databases from Ontario, British Columbia, and Alberta, Canada, and included living female kidney donors aged 18 to 42 years who donated a kidney between July 1992 and August 2021 and later experienced singleton pregnancies lasting at least 20 weeks’ gestation. These pregnancies were matched in a 1:4 ratio with singleton pregnancies of at least 20 weeks’ gestation among female non-donors. Pregnancies in donors and non-donors were matched based on delivery date, age at delivery, time elapsed between cohort entry and delivery, number of previous pregnancies, and income.

Final follow-up extended until March 2023. Outcome analysis was conducted from August 2024 to September 2026. The primary outcome was a composite measure of hospitalization with a diagnosis of gestational hypertension, preeclampsia, or eclampsia. Secondary outcomes comprised 12 maternal, fetal, and neonatal adverse events, including the individual elements of the primary outcome, the composite of low birth weight or preterm birth, and small for gestational age at birth.

The study comprised 385 pregnancies in 252 living kidney donors (average [SD] age, 27.8 [5.0] years) matched with 1540 pregnancies in 1535 non-donors (average [SD] age, 27.0 [4.8] years). The main combined outcome of gestational hypertension, preeclampsia, or eclampsia was observed in 46 donor pregnancies (11.9%) and 128 non-donor pregnancies (8.3%; risk ratio, 1.51; 95% CI, 1.10-2.08).

Out of the 12 secondary outcomes, the 95% confidence interval for the risk ratio excluded 1.00 for the small for gestational age outcome, which occurred in 53 donor pregnancies (13.8%) and 121 non-donor pregnancies (7.9%) (risk ratio, 1.86; 95% CI, 1.37-2.52). Overall, this cohort study determined that pregnancy following living kidney donation was linked to an increased risk of a combined outcome involving hospitalization with a diagnosis of gestational hypertension, preeclampsia, or eclampsia, in comparison to pregnancies in non-donors. 

Reference:

Wang, C., Naylor, K. L., McArthur, E., King, J. A., Sontrop, J. M., Beyene, J., Connaughton, D., Hendren, E., Hladunewich, M., Lam, N. N., Lentine, K. L., Lyons, R., McDonald, S. D., Roshanov, P. S., Youngson, E., & Garg, A. X. (2026). Pregnancy outcomes after living kidney donation. The Journal of the American Medical Association. https://doi.org/10.1001/jama.2026.21737