By Mariya Stratilatova, MD

Pregnancy in a woman with end-stage renal disease (ESRD), especially those on dialysis, is uncommon and carries serious risks for a woman and her baby. Should a woman with ESRD have a well-functioning kidney transplant, her chances for successful pregnancy significantly increase. Here, we will discuss chances of getting pregnant, risks and special considerations of pregnancy in dialysis or transplant patients.

Chances of Pregnancy in Women on Dialysis

Fertility, the ability to become pregnant, is significantly reduced in women with ESRD. When the term dialysis is used in this article, it stands for peritoneal dialysis (PD) and hemodialysis (HD) as the risks and outcome are the same in both therapies. Only 42 percent of women of childbearing age on dialysis have regular menstrual periods. Many of them have an anovulatory cycle, which means their eggs are not released from the ovary and cannot be fertilized. Fertility in women on HD is about 0.5 percent per year, which means only one in two hundred women of childbearing age on HD gets pregnant annually. This is about 40 times less than in women without ESRD. Fertility rate in women on PD is even lower, about one-half to one-third of that of HD patients.

Should a woman on dialysis become pregnant, her chances of having or losing her baby are, at best, 50:50. Only two-thirds of pregnancies continue beyond three months, and of these, 21 percent end in spontaneous abortion while 8 percent go on to stillbirth. Chances of a successful pregnancy are significantly higher in women who still have some renal function while on dialysis, or if pregnancy occurred before dialysis started.

Risks & Complications of Pregnancy

Hypertension (HTN), uncontrolled high blood pressure, is the major risk for a pregnant woman with ESRD and her baby. HTN occurs or worsens in 80 percent of pregnant women on dialysis. HTN is a major cause of prematurity and can be life threatening for mother and baby. Major risks of HTN in pregnancy are bleeding from the placenta and pre-eclampsia (“toxic” condition) and/or eclampsia (convulsions). Those are serious conditions that can cause a buildup of excess water throughout the body and lungs, bleeding disorders and convulsions. The only way to control these conditions is to deliver a baby as soon as possible, very often way before term and by Cesarean-section. Uncontrolled HTN can also cause stroke and loss of vision from bleeding in the back of an eye.

Other maternal complications include anemia and infection, especially peritonitis in women on PD. Peritonitis (infection of the lining of the abdomen) can result in miscarriage or premature labor.

Risks and Complications for Babies Born to Mothers on Dialysis

Prematurity and complications of prematurity, mainly an inability to breath on their own due to immature lungs, are major risks for babies born to mothers on dialysis. Eighty-five percent of those babies are born prematurely, a quarter of them are severely premature. All premature babies have a low birth weight and 28 percent are small for gestational age. As a result, 18 percent of live born babies die in perinatal period. Out of those who survive, 10 percent have congenital abnormalities and 20 percent have long term medical problems.

Major causes of prematurity include maternal HTN (due to poor blood supply to the baby via the placenta), polyhydramnios (excess fluid surrounding the baby due to excessive urination by the baby carried by a uremic woman) and premature rupture of membranes.

Management of Pregnant Women on Dialysis

To increase baby survival, the dialysis schedule has to be changed to increase the duration of dialysis to at least 20 hours per week. Daily dialysis is probably the best choice. For PD patients, dialysis time has to be doubled, and number of exchanges increased. Some data suggests that increasing dialysis time to 20 hours per week and lowering pre-dialysis BUN to less than 50 can increase baby survival up to 75-80 percent.

Blood pressure needs to be tightly controlled, which can be achieved with daily dialysis and blood pressure medications. Certain classes of blood pressure medications, such as ACE inhibitors and ARB’s have to be avoided. ACE inhibitors decrease blood pressure by opening or dilating blood vessels. ARB’s work by blocking the hormone that causes blood vessels to narrow. They can cause lung problems in a baby, including death from respiratory failure, as well as limb contractures. Diuretics, or water pills, also need to be avoided or used with extreme caution and only if prescribed by a doctor. Hypotension (low blood pressure) can also be dangerous, leading to fetal distress. Fetal monitoring during dialysis is advisable.

Another potential complication, namely anemia, requires doubling doses of Epogen and increasing doses of iron supplements. Use of intravenous iron is controversial.

Pregnancy after Kidney Transplantation

Incidence of pregnancy in transplant patients is 12-20 percent, which is significantly greater than in dialysis patients. If a woman has a well-functioning kidney transplant, her chances of having a healthy baby are about as good as for a woman without kidney disease. If a transplanted kidney works well, getting pregnant will not risk the kidney.

Outcomes of pregnancy solely depend on pre-pregnancy renal function. If a woman has a pre-pregnancy serum creatinine level of less than 1.4 mg/dl (less than 1.75-2 in some studies), chances of having a successful pregnancy are 96 percent. Only 30 percent of those with a well-working kidney transplant will develop pregnancy-related complications. However, if a pre-pregnancy creatinine is more than 1.4 mg/dl, the outlook for a successful pregnancy drops to 70-75 percent. One-third of these pregnancies end in therapeutic or spontaneous abortions.

Risks and Complications of Pregnancy in Kidney Transplant Patients

A major concern for kidney transplant recipients is whether pregnancy will worsen renal function and lead to graft loss. Pre-transplant creatinine and time elapsed since transplantation, are the best predictors of renal function. Overall risk of graft loss is 10-15 percent. A woman with normal renal function (pre-pregnancy creatinine less than 1.4 mg/dl) is likely to preserve her renal function. Should the pre-pregnancy creatinine elevate, especially when there is protein in the urine, there is a real risk that kidney function will worsen during pregnancy with permanent loss of some function. Potential causes of worsening renal function in a pregnant transplant patient include pre-eclampsia, acute or chronic rejection, recurrent kidney disease, dehydration, obstruction and medication toxicity.

Pregnant transplant patients also risk infections, such as a urinary tract infection (UTI). Forty percent of transplant patients develop a UTI during pregnancy. If left untreated, a UTI can lead to the loss of a kidney. Other “silent” infections may be reactivated during pregnancy and transmitted to the baby (herpes, cytomegalic virus, hepatitis and toxoplasmosis). Women intending pregnancy should be screened for these infections.

Risks for Babies Born to Transplant Recipients

Prematurity remains the main problem in babies born to kidney transplant recipients. The severity of this risk depends on maternal renal function and blood pressure control. Higher pre-pregnancy creatinine and uncontrolled HTN are associated with higher incidence of prematurity and its complications.

Immunosuppressive drugs create a special concern in pregnant transplant recipients. Some of these medications have definite risks for babies, but none that are widely used cause congenital abnormalities.

Immunosuppressive Medications

Prednisone, in low doses, is believed to have no significant adverse effects on babies. However, high doses can cause adrenal insufficiency. This drug is still used for acute rejection and babies can be treated if necessary.

Azathiprine is considered to be safe, but can cause low white blood cell (WBC) count in babies, especially if a mother also has a low WBC. White blood cells help fight infections.

Cyclosporine is associated with a higher risk of pre-eclampsia and smaller gestational age babies. However, women treated with cyclosporine are usually sicker before pregnancy (have worse renal function or higher blood pressure), so it is unclear whether medications or pre-existing medical conditions in the mother cause those risks. Tacrolimus use has been limited in pregnant patients. In babies, it can cause high potassium and poor urine output, which eventually resolves.

Management of Pregnant Transplant Recipients

Optimization of immunosuppressive medications and blood pressure control remain major goals of a medical team when caring for a patient. Frequent monitoring of renal function is essential. Sometimes, a kidney biopsy is required to find the exact cause and start proper treatment. For example, treatment for pre-eclampsia is delivery of the baby, but steroids should be given for rejection. Hypertension has the same potential risks as in dialysis patients and can be controlled with the same medications.

Risks of acute rejection are usually minimal within two years of transplantation, when immunosuppressive medications have been adjusted. Therefore, it is advisable to plan pregnancy at least two years after the transplant.

What Else Your Doctor Should Tell You

Even though only few women with ESRD become pregnant, the possibility of pregnancy has to be addressed by a kidney doctor or physician assistant. If a woman does not plan to have a child, she needs to practice birth control. Birth control pills can increase risks of blood clots in patients with lupus and antiphospholipid antibody syndrome and in transplant recipients. Intrauterine devices have a risk of infection, such as peritonitis in PD patients.

Dialysis patients desiring pregnancy should be advised to delay until after kidney transplantation. Should pregnancy occur while on dialysis, the risks and medication changes must be promptly planned and initiated. For example, antihypertensive drugs must be adjusted to protect the baby. Vitamin supplements and folic acid should be added. Because absence of menstrual periods and elevated b-HCG (marker of pregnancy in the blood) are common in dialysis patients, a suspected diagnosis of pregnancy must be confirmed by a sonogram. A team of dialysis doctors, obstetricians, nurses and dieticians experienced in high risk pregnancies and ESRD should plan close monitoring and optimized care.

Key Points

• For dialysis patients, chances of getting pregnant are significantly lower than for those with a kidney transplant or without ESRD.

• Only one-half of pregnancies in dialysis patients result in a surviving baby.

• Successful kidney transplantation significantly increases the chances of having a baby, approaching those of non-ESRD women.

• Uncontrolled hypertension is the major risk factor for complications.

• In pregnant dialysis patients, dialysis time is usually increased in frequency and duration.

• In transplant patients, risk of worsening kidney function, including graft loss, depends on pre-pregnancy renal function.

• Pregnant ESRD patients require close monitoring by a team of experienced medical professionals.

Mariya Stratilatova, MD, born in St. Petersburg, Russia, came to the United States in 1989 as a refugee. Dr. Stratilatova graduated from medical school in 2002 and started her Internal Medicine residency at SUNY Downstate in Brooklyn, NY.

This article originally appeared in the January 2005 issue of aakpRENALIFE, Vol. 20, No. 4.

Back