During my nephrology fellowship, I was asked by a renal transplant recipient at her 9-month post transplant clinic visit “Doctor, can I become pregnant? Will I have a live healthy baby? Will my kidney function get affected?” I did not have clear answers then and read extensively on the subject.
**below, I will summarize what I have learned about pregnancy in kidney transplantation, please consult your nephrologist before you consider pregnancy if you have a kidney transplant**
The first successful pregnancy in kidney transplant recipient occurred in 1958 to the 23 year old Edith Helm who had received a kidney from her identical twin sister Wanda Foster. Thus, this occurred not long after the first kidney transplant in 1954. She delivered a healthy full term boy of 3300 grams by cesarean section 2 years after her transplant. Interestingly, even her donor and twin sister Wanda Foster gave birth four times successfully after kidney donation.
Chronic kidney disease is associated with disruption of hypothalamic gonadal axis primarily causing hyperprolactinemia and anovulation due to absence of the luteinizing hormone surge.
Pregnancy is rare in women with ESRD with the incidence of conception ranging from 0.9 to 7%. Kidney transplantation is associated with normalization of the reproductive hormones and restoration of fertility as soon as 6 months after transplantation and gives us an apparent large window of opportunity to help women of childbearing age who want to have babies. On the other hand, deteriorating allograft function may narrow this window unpredictably. In addition, pregnancy in kidney transplant recipients is challenging due to the side effects of immunosuppressive medications, and higher risk of adverse maternal and fetal complications. Therefore, It becomes important as physicians to counsel and medically optimize kidney transplant recipients who wish to become pregnant.
I have put below common questions that are frequently asked by women with history of kidney transplant.
Question: Is pregnancy possible after a kidney transplant?
Answer: Yes, pregnancy is possible in kidney transplant recipients. However, there are several important things that one must consider before you decide to conceive like timing of conception, risk and changes in immunosuppression that we have discussed below. It is extremely important that you talk to your transplant nephrologist about this beforehand.
Question: What is the likelihood of maternal complications if I do decide to get pregnant?
Answer: There is a 6 fold higher likelihood of preeclampsia in women who have a kidney transplant and a reported incidence of 15-25%. There is a also 5 fold higher risk of needing a cesarean section. However, there is no increased risk of maternal mortality.
Question: Will I have a live healthy baby?
Answer: Likely Yes, having had a kidney transplant does not increase fetal mortality, especially if the timing is right and adequate precautions are taken (see below). However there is a 12 fold high likelihood of preterm and low birth weight babies; and a 3 fold higher likelihood of having small for gestational age babies.
Question: What are the risk factors associated with poor maternal and fetal outcomes?
Answer: The two most important risk factors are serum creatinine > 1.4 mg/dl, presence of hypertension during pregnancy and proteinuria > 500 mg/24h. It is advisable to become pregnant sooner than later - younger age at conception is associated with better outcome.
Question: What is the optimal time to conceive?
Answer: The optimal time to conceive is after 6 months and within 2 years of getting the transplant. It is known that if time to conception is more than 2 years of getting a transplant, it reduced the likelihood of viable fetal outcomes.
Question: Will pregnancy affect my allograft function?
Answer: Likely No, the kidney allograft is able to adapt normally to physiological changes of hyperfiltration in pregnancy. An uncomplicated pregnancy does not increase the risk of kidney loss. However it may affect graft function if you have risk factors like higher pre-pregnancy creatinine (or lower kidney function) or develop hypertension during pregnancy.
Question: What are the changes in immunosuppression that are made if I wish to become pregnant?
Answer: Mycophenolic acid (cellcept) and sirolimus are teratogenic, and must be stopped 6 weeks prior to conception. Cellcept has shown to be associated with limb and facial anomalies tacrolimus/cyclosporine (class C), azathioprine (class D) and low dose maintenance prednisone (< 20 mg/day) (class B) are safe to be used during pregnancy. Even though azathioprine is listed as class D, it is to safe to be used during pregnancy because the fetal liver lacks the enzyme inosinate pyrophosphorylase that converts it to active metabolite 6 mercaptopurine; and fetus is protected from its adverse effect.
Question: My friend wants to donate a kidney. Will donating a kidney affect her future pregnancy?
Answer: Likely No, donating a kidney does not affect the chances of her becoming pregnant. Post-donation, however, there is a 2.5 fold higher risk of preeclampsia and gestational hypertension in living donors, without any associated fetal complications.
Question: I am currently on dialysis. Should I try to become pregnant now or wait till I get a kidney transplant?
Answer: The incidence of conception on dialysis patients is very low ranging from 1-7%. Even when women with ESRD are able to conceive, the incidence of live birth is 20-40%. Women should be advised to wait till they get a transplant. However if the wait list for transplant is long due to high PRA or they are getting older, they may be advised to try to conceive while on dialysis. How Intensification of dialysis to >36 hours per week is associated with improved fetal outcomes with a live birth rate of 85%.
For a review of Pregnancy in Kidney Transplant review its entry in NephMadness ‘15.
Post by Silvi Shah, NSMC Intern