Family planning and kidney disease: Pregnancy

With help from nephrologist (and one of our former Clinical Scientist in Nephrology fellows), Dr. Jessica Tangren, AKF is answering questions about family planning and kidney disease in a three-part series. Part one focuses on fertility and sexual health, part two on pregnancy and part three focuses on labor and delivery and postpartum. This is part two: pregnancy.

Can women with kidney disease get pregnant?

Yes! 

"Kidney disease is not at all an absolute barrier to having a family and to having your own children," said Dr. Tangren. 

Is this true for any stage of kidney disease?

Yes! 

"I have had patients who have had successful pregnancies from the mildest stage of kidney disease all the way to women on dialysis," said Dr. Tangren.

Dr. Tangren did warn, though, that the more advanced stages of kidney disease are associated with higher risks during pregnancy. 

Regardless of your stage of kidney disease, planning is key for improving your chances of having a successful pregnancy. 

"Planning, planning, planning. It's much easier to plan and to make medicine changes and get everything optimized beforehand. It's much harder once you're already pregnant," said Dr. Tangren.

What impact does kidney disease have on pregnancy?

"The good news, in general, is that from very large studies, [it] doesn't seem to be that kidney disease itself increases your risk of having any major fetal malformations [when the baby does not develop the way it should]," said Dr. Tangren. 

However, studies show that kidney disease can negatively impact pregnancy. The most common complication of pregnancy in women with kidney disease is preeclampsia. Preeclampsia is when the placenta — which provides oxygen and nutrition to the baby through the umbilical cord — does not develop normally. When this happens, the placenta "can release factors that can make mom and baby sick," according to Dr. Tangren. Less than 5% of healthy women develop preeclampsia, but more than 20% of pregnant women with kidney disease do.

Fortunately, Dr. Tangren said that if you plan ahead for your pregnancy, you and your doctor can work to optimize your kidney disease or other related conditions (like high blood pressure) to make pregnancy as safe as possible for you.

What impact does pregnancy have on kidney disease?

Kidneys play an important role in adapting to normal pregnancy. There are several changes to your kidneys and their functions during pregnancy, which can put additional stress on your kidneys. This may cause additional damage if you already have kidney disease. 

"We do know that pregnancy can accelerate loss of kidney function," explained Dr. Tangren. "But we see it more often with more advanced stages of kidney disease, and fortunately it's a lot less common than we previously thought."

Also, Dr. Tangren cited the "wise words of her mentor" Dr. Michelle Hladunewich (a nephrologist and kidney disease in pregnancy expert from Toronto, Canada), who has a "Three Strikes Rule": (1) Elevated serum creatinine (greater than 1.4), (2) proteinuria and (3) uncontrolled hypertension (high blood pressure; greater than 140/90). These conditions together put a woman at highest risk for complications in pregnancy. 

Additionally, pregnant women who do not have kidney disease may also be at risk for developing kidney problems, as "preeclampsia and other pregnancy-related complications are among the most common causes of AKI [acute kidney injury] in young women."

Will having kidney disease affect your baby in any way? Does it increase the chances your baby could have kidney disease or other health concerns?

Not necessarily. 

If you have a genetic kidney disease, then there is a possibility that your baby will inherit the genes for that disease. Fortunately, you and your partner can undergo genetic screenings prior to getting pregnant to determine the chance that your baby will inherit the disease. There are also options to test the genes of your baby early in the pregnancy. If you are choosing to do invitro-fertilization (IVF), you can also do a genetic testing of embryos prior to transfer. 

If you do not have a genetic kidney disease, pregnancy-related complications like preeclampsia and early delivery (which women with kidney disease are at a higher risk of having) may impact your baby's kidney function.

"There's a lot of interest in understanding the risk of kidney disease in premature babies because we think they're born with fewer nephrons [the filtering units in the kidneys that help remove waste and toxins from the blood]," said Dr. Tangren. "And so, in that sort of indirect way, prematurity can be linked with kidney disease later in life. The magnitude of this risk is quite small, however."

Certain medicines that are used to manage kidney disease — like angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) and many medicines used to prevent kidney transplant rejection like mycophenolate — are teratogenic. Teratogenic means that they can impact the development of the baby and potentially lead to malformations. This is true even early in pregnancy, so it is important to talk with your doctor about your medicines before getting pregnant.

What impact will pregnancy have on your dialysis treatments? 

The short answer: you will likely have your dialysis treatments more often and with longer treatment times. "We recommend that most women need probably upwards of 24, if not even higher like 36 hours a week of dialysis," said Dr. Tangren. However, this depends on how well your kidneys are functioning. 

Researchers found that more intense dialysis of five to six days a week for three to four hours had better outcomes for pregnancies. "Intensified dialysis during pregnancy has been a game-changer for successful outcomes for pregnant women," explained Dr. Tangren. She also added, "It is definitely a full-time job."

The plus side, though, is that receiving this much dialysis often means your labs "look like [you] don't have kidney disease." 

Despite the time and physical commitments of this regimen, Dr. Tangren noted that she had many patients who were willing to go through it all again to have another child. "And I think oftentimes that at face value, a health care provider would be like, 'You're crazy. Why would you ever want to do that again?' But if you talk to these patients about why they're doing it, you learn amazing things about people. It's one of the best parts of my job is to help people get to these goals." 

Both pregnancy and kidney disease have recommended foods or drinks to avoid. Do those overlap? Or will pregnancy affect a patient's ability to follow a kidney-friendly food and fluid plan?

Like with many of these questions, it depends on your situation and what stage of kidney disease you have.

"I have not run into many concerns about diet in all honesty from my pregnant patients on dialysis," said Dr. Tangren. "Actually, the dietary restrictions get easier because you're getting so much dialysis that oftentimes things like restricting phosphorus, restricting protein and things like that, [can be eased]." 

She did note that women on dialysis may have to adjust the recommended supplements for pregnancy, including prenatal vitamins and folic acid. "Folic acid is a water-soluble vitamin that is cleared during dialysis," explained Dr. Tangren. "So, women on dialysis who are pregnant need to eat extra folic acid supplementation to make sure they're getting enough."

Overall, Dr. Tangren said that pregnancy will not affect your kidney-friendly food and fluid plan, but you should talk with your doctor about what you need. 

Any additional considerations for pregnancy – from conception to birth – if you are living with a kidney transplant? 

"Definitely talk to your transplant doctor about the ideal timing of having a pregnancy after transplant," said Dr. Tangren. She explained that you will need to ensure you are using pregnancy-safe immunosuppression medicine(s).

The other important consideration she mentioned is cytomegalovirus (CMV). "Unfortunately, some of the infections that are more common in transplant patients can be problematic during pregnancy," said Dr. Tangren. "CMV is the one we worry about the most… because CMV is one of those infections that can transmit through the placenta and impact the developing fetus."

Dr. Tangren suggested that if you have a history of CMV or if your kidney donor had a history of CMV, talk to your doctor and make sure it has cleared completely before you become pregnant. 

Are the medicines that you take after transplant safe for pregnancy?

Yes. There are pregnancy-safe immunosuppression medicines.

However, the most common medicine used as part of anti-rejection therapy for kidney transplant recipients (mycophenolate) is not safe for pregnancy. Mycophenolate is teratogenic, which means that if the fetus is exposed to the drug, it may not develop properly. If you are on a mycophenolate medicine and want to become pregnant, talk to your doctor about what alternative medicine you can take.

"With transplant patients, planning is so important because you really want to be off your mycophenolate before you conceive because there's high rates of miscarriage and high rates of fetal malformations, even with first trimester exposure to mycophenolate," said Dr. Tangren.

If you were a living donor, are there any considerations you need to think about when trying to get pregnant or while pregnant?

According to a study published in 2015 in the New England Journal of Medicine, there is a possibility that you are at greater risk of developing a hypertensive (high blood pressure) disorder in pregnancy. "There's a slight increase of having blood pressure problems during pregnancy, but I think the good news was that the outcomes for all of the offspring and for all of the women were great," said Dr. Tangren. She added, "It's something that transplant physicians now counsel donors or potential donors, if they're in their reproductive age, but it has never, as far as I know, been a reason that they would not consider accepting you as a donor."

To find out more about kidney disease and pregnancy, you can watch the webinar Dr. Tangren did with AKF, "Pregnancy and Kidney Disease," or this session from AKF's 2024 Kidney Action Week™. 

To find out more about kidney disease and fertility and sexual health, check out part one in this family planning and kidney disease series.

To find out more about kidney disease and labor and delivery and postpartum, check out part three in this family planning and kidney disease series. 

Disclaimer:The information provided here is not intended to replace professional medical advice, diagnosis or treatment. Please consult your obstetrician (OBGYN), primary care doctor and/or nephrologist about your specific family planning needs and goals.