Because people who donate kidneys are healthier than the general population, we restricted the general population to people who did not have a health condition that would preclude donation. We created a simulated donation date in the rest of the population and then excluded 35 conditions, such as kidney disease, high blood pressure, lupus, and chronic infections, because people with those conditions would not be eligible to be donors. Then we matched the donors and non-donors on other characteristics associated with the outcome, like parity, income, calendar year, etc.

HCPLive: How did pregnancies in kidney donors compare with those in nondonors?

Garg: We ended up comparing 385 donor pregnancies and 1,540 matched healthy non-donor pregnancies. We did notice a higher risk of gestational hypertension or preeclampsia in the donors compared to the non-donors: rounded off, around 12% in the donors compared to 8% in the non-donors. But overall, many of the pregnancies in donors were healthy, with no difficulty for the mother or child.

We looked at a number of secondary outcomes as well, and the one that caught our attention is small for gestational age, which was also a bit higher in the donors vs non-donors. Because we looked at many outcomes, whether this is due to chance or something biologically occurring is something we need to sort out in the future.

So overall, the study shows that people who become pregnant after donation generally have very healthy pregnancies and healthy children. There’s a modest increase in the risk of developing high blood pressure or preeclampsia during those pregnancies, and the signal we saw for small for gestational age children warrants some further investigation.

Read more: Interpreting Kidney Donor Pregnancy Signals

HCPLive: Why might small for gestational age births have been more common in donor pregnancies?

Garg: One possibility is chance, particularly given the number of secondary outcomes we examined. At the same time, there is biological plausibility. Reduced kidney function may impair normal renal adaptation to pregnancy and, in turn, affect placental development and blood flow. So, this finding warrants evaluation and confirmation in future studies.

HCPLive: Could genetics explain the pregnancy risks seen in kidney donors?

Garg: The paper also discusses some limitations of the study, including the possibility of genetic confounding. About two-thirds of the donors were first-degree relatives of the recipient, whereas very few non-donors would be expected to have a first-degree relative with kidney failure. So inherited susceptibility could potentially contribute to the association we observed.

There are, however, several important pieces of context. All donors were required to have normal measures of kidney health at the time of evaluation. The subsequent pregnancy occurred on average 6 years later. In approximately one-third of donors who had a pregnancy before donation, none had recorded gestational hypertension or preeclampsia in those pregnancies. In Canada, individuals with these complications would generally not be accepted as living kidney donors while still of childbearing age.

So certainly, genetic confounding remains possible, but these observations make it less likely to fully explain the observed association. We have donors and non-donors, but two-thirds of the donors are related to recipients, so maybe they have genetic risk factors for what we observed. We don’t think that’s explaining the observation, but it’s something we considered.

Read more: Counseling Kidney Donors on Future Pregnancy

HCPLive: Will donating a kidney affect future pregnancies?

Garg: For patients with advanced kidney disease, a kidney transplant offers the chance for a longer and healthier life, especially a transplant from a living donor. Many generous people come forward to donate a kidney to a family member or friend in need, but for those who may become pregnant in the future, there is an important question: Will donating a kidney affect my future pregnancies? That’s the question we addressed in this study.

HCPLive: What do the findings mean for living kidney donation?

Garg: We feel the most recent clinical practice guidelines are still very relevant. When we evaluate people who are interested in becoming donors and are thinking about becoming pregnant afterward, we counsel them on what to expect in terms of those pregnancies and this potential increased risk of gestational hypertension or preeclampsia.

However, this does not preclude donation. If someone is interested in having a pregnancy after donation, that doesn’t preclude them from being a donor. As I mentioned, most of the pregnancies were uncomplicated, so they can be enabled by the transplant center to donate.

We can also encourage healthy lifestyle behaviors. Obesity, for example, is associated with a higher risk of preeclampsia, so ensuring people stay healthy after donation and are monitored appropriately for these complications is important.

My final comment is that over 80 countries perform living kidney donor transplantation worldwide. When transplant centers enable a living kidney donor transplant, they should be confident the person will have access to good maternal care should they become pregnant in the future.

HCPLive: How should clinicians counsel kidney donor candidates about pregnancy?

Garg: These findings support the 2017 KDIGO living kidney donor practice guidelines. When we evaluate donor candidates, we should ask about future pregnancy plans. A desire for future pregnancy is not a contraindication to donation, as most post-donation pregnancies remain uncomplicated. When we counsel donor candidates, we should discuss the possible effect of donation on future pregnancy, including a higher risk of gestational hypertension or preeclampsia.

Editor’s Note: Garg reported no relevant disclosures. This transcript has been edited for grammar and clarity using artificial intelligence tools.

References

Wang C, Naylor KL, McArthur E, et al. Pregnancy outcomes after living kidney donation. JAMA. Published online October 22, 2026. doi:10.1001/jama.2026.21737Garg AX. Pregnancy outcomes after living kidney donation. Presented at: American Society of Nephrology Kidney Week 2026; October 22, 2026; Denver, CO. Abstract TH-OR117.