Canadian study links kidney donation to preeclampsia risk
- Living kidney donation is associated with a modest increase in the risk of gestational hypertension and preeclampsia, though the vast majority of subsequent pregnancies remain uncomplicated, HCPLive reported.
- The findings emerged from a Canadian matched cohort study published online October 22, 2026, in JAMA and presented concurrently in Denver at American Society of Nephrology Kidney Week...
- Researchers utilized linked healthcare administrative databases covering residents in Ontario, British Columbia, and Alberta under Canada's universal healthcare system.
Living kidney donation is associated with a modest increase in the risk of gestational hypertension and preeclampsia, though the vast majority of subsequent pregnancies remain uncomplicated, HCPLive reported.
The findings emerged from a Canadian matched cohort study published online October 22, 2026, in JAMA and presented concurrently in Denver at American Society of Nephrology Kidney Week 2026. Amit X. Garg led the research.
Canadian Health Database Analysis Tracks 385 Donor Pregnancies
Researchers utilized linked healthcare administrative databases covering residents in Ontario, British Columbia, and Alberta under Canada’s universal healthcare system. The analysis examined 385 pregnancies among 252 women aged 18 to 48 who were living kidney donors between July 1992 and August 2021.
To establish a valid baseline, investigators restricted the general population comparison group to individuals without health conditions that would disqualify them from organ donation, excluding 35 conditions such as pre-existing kidney disease, chronic infections, lupus, and high blood pressure. Donors were then matched against 1,540 healthy non-donor pregnancies among 1,535 individuals. Matching accounted for parity, maternal age at delivery with a mean of 33 years, calendar year, income, number of prior pregnancies, and interval since the last pregnancy.
Hospitalization Risks for Preeclampsia and Gestational Hypertension Rise Modestly
The primary outcome measured a composite of hospitalizations for gestational hypertension, preeclampsia, or eclampsia. Healio reported that this composite outcome occurred in 11.9% of pregnancies among kidney donors compared with 8.3% among matched non-donors, yielding a relative risk of 1.51.
The absolute increase was modest, and these disorders were generally first recorded close to term,
Garg told Healio, adding that fewer than 2% of pregnancies in either cohort recorded the outcome before 34 weeks of gestation.
Among secondary endpoints evaluated across 12 maternal, fetal, and neonatal measures, two showed statistically significant increases in donors: preeclampsia or eclampsia individually at 1.52 relative risk, and infants born small for gestational age below the 10th percentile at 13.8% for donors versus 7.9% for non-donors.
Clinical Practice Guidelines Emphasize Pre-Donation Family Planning Counseling
Clinical evaluators must continue routine discussions regarding future family planning with prospective living donors, aligning with current 2017 KDIGO practice guidelines. Garg emphasized that a stated desire for future pregnancy does not disqualify a candidate from donating a kidney, given that most post-donation pregnancies proceed without complications.
Transplant centers enabling living donations should verify that participants retain access to robust maternal healthcare services. Clinicians also point to lifestyle factors such as obesity management and postpartum monitoring as critical components of post-donation care.
Unresolved Genetic Factors and Future Research Directions
Investigators continue to evaluate whether inherited susceptibility plays a role in the observed pregnancy signals. Approximately two-thirds of the kidney donors in the study were first-degree relatives of the transplant recipients, introducing the possibility of shared genetic risk factors for vascular and renal complications.
Researchers note that the secondary finding involving infants born small for gestational age requires further confirmation to determine whether it stems from chance across multiple secondary comparisons or biological mechanisms such as impaired renal adaptation affecting placental blood flow.