A diagnosis of chronic kidney disease (CKD) means the kidneys are damaged and cannot filter blood effectively, which may eventually require dialysis. For women receiving dialysis, the question of pregnancy is complex, yet a successful birth is possible. Pregnancy while on dialysis is considered rare and high-risk, but improvements in medical management have significantly increased the live birth rate from around 20-30% decades ago to nearly 80% in modern practice. This outcome requires intense, specialized medical care. This article will explain the unique challenges of conception, the elevated risks for both mother and baby, the necessary adjustments to treatment, and the care required after delivery.
Fertility Challenges While on Dialysis
The physiological state of chronic kidney failure and the resulting uremia create significant obstacles to conception for women on dialysis. The primary issue is a disruption of the normal hormonal communication pathway between the brain and the ovaries, known as the hypothalamic-pituitary-gonadal axis. This hormonal imbalance leads to irregular or absent menstrual cycles, a condition called amenorrhea, which occurs in about two-thirds of women undergoing dialysis.
Uremia, the buildup of waste products in the blood, interferes with the release of hormones necessary for ovulation. High levels of the hormone prolactin are common because the kidneys cannot clear it efficiently; this excess prolactin can prevent the release of an egg. Even when a woman experiences a menstrual period on dialysis, the cycle is often anovulatory, meaning no egg is released for fertilization. Due to these factors, pregnancy in women on chronic dialysis is rare, occurring about 40 times less frequently than in the general female population.
Risks to Mother and Baby
Once pregnancy is achieved, the condition presents substantial risks for both the mother and the developing fetus, mainly because the underlying kidney failure creates a toxic environment. The most common maternal complication is preeclampsia, characterized by high blood pressure and organ damage, which affects up to 40% of pregnant women on dialysis. This rate is significantly higher than in women with normal kidney function. Mothers also face a heightened risk of anemia, which must be carefully managed with medications to ensure adequate oxygen delivery to the fetus. Furthermore, maintaining proper fluid balance is difficult, increasing the risk of fluid overload and worsening cardiovascular status.
The buildup of waste products, known as uremia, is directly linked to complications that affect the baby. For the baby, the risks are primarily associated with prematurity and poor growth. Preterm delivery, defined as birth before 37 weeks, occurs in about 80% of these pregnancies, often requiring delivery earlier than planned. The high levels of waste in the mother’s blood, particularly blood urea nitrogen (BUN), are strongly correlated with low birth weight and intrauterine growth restriction (IUGR). High BUN levels are also thought to increase the risk of polyhydramnios (excessive amniotic fluid), which can trigger premature labor.
Adjusting Dialysis Treatment for Pregnancy
Managing a pregnancy while on dialysis requires a fundamental shift in treatment intensity, moving far beyond the standard three-times-per-week schedule. The goal is to maximize the removal of uremic toxins to create a healthier environment for the fetus and mitigate the risks of complications.
The most critical management target is the predialysis blood urea nitrogen (BUN) level, which is a marker for the amount of waste in the blood. The goal for pregnant women is to maintain the BUN concentration below 50 mg/dL, with some specialists aiming for less than 35 mg/dL. Achieving this low BUN target is directly associated with better fetal outcomes, including a longer gestational age and higher birth weight.
Hemodialysis Adjustments
For women on hemodialysis, this means increasing the frequency and duration of treatment, often to six sessions per week, totaling 20 to 36 hours weekly.
Peritoneal Dialysis Adjustments
For those on peritoneal dialysis (PD), the protocol must also be intensified with more frequent and higher-volume exchanges to improve clearance. Pregnancy can be more challenging with PD due to increased abdominal pressure, which may lead to discomfort or interfere with the catheter.
Regardless of the dialysis modality, maternal and fetal monitoring is increased, including frequent ultrasounds and fetal non-stress tests, to track the baby’s growth and well-being.
Care and Monitoring After Delivery
The immediate period following delivery requires careful and prompt management to transition the mother back to a stable, non-pregnant state. The intensive dialysis schedule implemented during pregnancy is quickly adjusted back to the patient’s standard, pre-pregnancy protocol. This return to the usual schedule is important because the physiological demands of pregnancy rapidly subside after the baby is born.
Fluid balance is a significant concern immediately postpartum, as the body begins to shed the extra fluids accumulated during pregnancy. Dialysis treatments must be precisely managed to prevent sudden fluid shifts that could lead to hypotension or other complications. Women with CKD require close monitoring of their kidney function and blood pressure in the six weeks following delivery.
Most mothers on dialysis are encouraged to breastfeed if they choose. The passage of waste products into breast milk is not a concern, and the patient’s entire medication list must be carefully checked for compatibility with lactation.