Saudi Journal of Kidney Diseases and Transplantation

LETTER TO THE EDITOR
Year
: 2011  |  Volume : 22  |  Issue : 3  |  Page : 552--553

Pregnancy after kidney donation - Placing things in perspective


Shobhana Nayak-Rao 
 Department of Nephrology, Bahrain Specialist Hospital, P.O. Box 10588, Manama, Bahrain

Correspondence Address:
Shobhana Nayak-Rao
Department of Nephrology, Bahrain Specialist Hospital, P.O. Box 10588, Manama
Bahrain




How to cite this article:
Nayak-Rao S. Pregnancy after kidney donation - Placing things in perspective.Saudi J Kidney Dis Transpl 2011;22:552-553


How to cite this URL:
Nayak-Rao S. Pregnancy after kidney donation - Placing things in perspective. Saudi J Kidney Dis Transpl [serial online] 2011 [cited 2022 Sep 28 ];22:552-553
Available from: https://www.sjkdt.org/text.asp?2011/22/3/552/80498


Full Text

To the Editor,

The practice of using living donors for kidney transplantation has been in vogue for more than 50 years and is thought to be a relatively safe procedure with few long-term undesirable effects for the donor. Long-term follow-up of living donors, in one study for up to 25 years, has revealed marginal increase in urinary protein and blood pressure with preserved glomerular filtration rate (GFR). [1],[2],[3] With female donors increasing in numbers to approximately 60% of the total living related donor pool, women in the reproductive age group ask whether they can safely become pregnant after donating a kidney. Till now, the answer to this question was based on anecdotal information rather than on published evidence. Two recent studies however have shed some light on this topic. Previous small, retrospective, single-center studies suggested that after kidney donation, women can have a normal pregnancy without significant problems and that donor nephrectomy was not detrimental to the outcome of future pregnancies. [4],[5]

Reisaeter et al analyzed data from the Medical Birth Registry of Norway, a database containing information of all pregnancies from 1967 onward. [6] The Norwegian Renal Registry provided records of kidney transplants performed between 1967 and 2002. The two data sources were linked and 326 donors with 726 pregnancies were identified. 620 pregnancies had occurred before donation and 106 were recorded after donation. Pregnancies before kidney donation as well as a random sample taken from the Medical Birth Registry served as controls. Rates of gestational hypertension, preeclampsia, birth weights and infant survival were compared between the groups. In unadjusted analysis (Fisher's test), no differences were observed in the occurrence of chronic hypertension, gestational hypertension, birth weight and infant mortality. The occurrence of stillbirths was 3/106 (2.8%) after donation, 7/620 (1.1%) before donation and 1.1% in the control general population (P = 0.17). A slightly higher incidence of pre-eclampsia was observed in post-donation pregnancies than before donation (5.7% vs. 2.6%; P = 0.026) according to the generalized linear mixed model.

The other study published [7] reported results of a survey of women who had donated kidneys. Out of 2,102 women donors, 1,589 donors responded to the pregnancy survey and 1,085 women reported 3,213 pregnancies. 504 reported none. According to donor responses, post donation (vs. pre-donation) pregnancies were associated with a lower likelihood of full-term deliveries (78.7% vs. 84.6%; P = 0.0004) and a higher likelihood of fetal loss (19.2% vs. 11.3%; P < 0.0001). Post-donation pregnancies were also associated with a higher risk of gestational diabetes (2.7% vs. 0.7%; P = 0.0001), gestational hypertension (5.7% vs. 0.6%; P < 0.0001), proteinuria (4.3% vs. 1.1%; P < 0.0001) and pre-eclampsia (5.5% vs. 0.8%; P < 0.0001). In women who had pre- and post-donation pregnancies, adverse maternal and fetal outcomes were more likely to occur in their post-donation pregnancies. However, the authors stated that pregnancy outcomes were comparable to published rates in the general population.

The results of these two studies raise the issue that although pregnancy outcomes after kidney donation seem to be comparable to those in the general population, donating a kidney may place a woman at slightly higher risk for complications than if she had not donated. Pregnancy is associated with numerous renal physiological changes including an increased renal plasma flow and GFR. Removal of one kidney and the ensuing glomerular hyperfiltration in the other kidney would at least theoretically alter renal hemodynamics and increase the predisposition to hypertension. Complications such as pre-eclampsia can have negative long-term consequences for both the mother and the baby, including an increased risk of cardiovascular disease for the mother and an increased stroke for the child. [8],[9],[10],[11],[12]

However, these studies have some limitations. They are retrospective in nature and are based on either registry diagnosis and/or survey results, which may be biased. Neither study, therefore, is definitive though they shed some light on this topic; the question of whether women can safely carry on a pregnancy after kidney donation remains largely unanswered. Based on the currently available evidence, it can be inferred that the vast majority of women donors can, but definite answers can be obtained only by prospective multicenter studies. This will be crucial in appropriately advising young women donors about future pregnancies.

References

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