Home Hemodialysis for Pregnant Patients: A Short Review and Case Report

Pregnancy has a profound effect on total body volume, intravascular volume, hemodynamics, and metabolism. The dramatic changes in volume, body weight, and clearance requirements pose challenging clinical decisions for the nephrologist. In addition to the physiological demands of pregnancy, the nephrologist must consider the economic, psychosocial, and pragmatic obstacles facing each patient. For example, patients may not have transportation or access to daily in-center dialysis, or they may have older children to care for or work responsibilities that may make daily dialysis difficult to access. Home hemodialysis (HHD) has undergone a revolution in technological advances with the creation of machines that are easier to use and more portable and use less dialysate than traditional in-center machines. These innovations have allowed more patients access to HHD.

The NxStage system may be used for short, daily or nocturnal HHD, and its innovation is the frequent, low dialysate-volume approach to clearance (1). The clearance prescription using the NxStage system is related to volume of dialysate and filtration fraction, and the time of treatment is determined secondarily. The physiological benefits of frequent dialysis, including improved blood pressure control and regression of left ventricular hypertrophy, are well-established (2).

There are limited data on the use of the NxStage dialysis modality in pregnancy. Three previous cases of successful pregnancies in patients using the NxStage system have been reported (3). As the use of frequent, low dialysate-volume approach modalities continues to expand, we proposed that this is a safe and recommended modality for the management of end stage kidney disease in pregnancy.

Here, we add another case to the literature of pregnancies resulting in live birth in patients using the NxStage machine for home dialysis.

A.C., a 29-year-old woman with kidney failure due to IgA nephropathy, became pregnant shortly after initiating dialysis. She was undergoing thrice-weekly in-center dialysis via fistula and had a peritoneal dialysis (PD) catheter placed in anticipation of transitioning to PD. Residual urine volume was 1200 mL/day. At the time of pregnancy, the initial prescription for in-center HD was 24 hours weekly (4-hour treatments, 6 days/week), which continued until transition to HHD at week 14 of gestation. In determining the NxStage dialysis prescription, we focused on maintaining a pre-HD blood urea nitrogen (BUN) under 50 mg/dL using daily dialysis treatments, based on the guidelines available at that time (in 2016) (4). Ultrafiltration was limited to 1 L/treatment to avoid hypotension. We allowed the estimated dry weight to rise liberally to avoid hypotension. The initial prescription was a filtration fraction of 33% with 30 L dialysate, which correlated to 4 hours/day, 7 days/week. At 25 weeks' gestation, the dialysate volume was increased to 35 L to maintain clearance goals, but due to pre-HD BUN levels remaining over 50 mg/dL, at 26 weeks' gestation, the volume of dialysate was increased to 50 L, and the patient started a nocturnal daily prescription with a time of 6.5 hours of treatment/night.

Secondary to the frequent and prolonged nature of dialysis treatments, the buttonhole cannulation technique was used. Weekly complete blood count and metabolic panels were monitored. Epogen and heparin were limited to single-dose vials, as recommended by the manufacturer to avoid exposure to benzyl alcohol. (Benzyl alcohol is a preservative in multi-dose vials.) Non-pregnancy-related complications included: 1) a fistulagram at 13 weeks' gestation, for which the patient was covered with three lead aprons to reduce radiation exposure and 2) a PD catheter exit site infection during the second trimester. There was a clinical decision to defer PD catheter removal until the pregnancy had completed. The PD catheter was removed at the time of delivery.

Pregnancy-related complications included: 1) hospitalization for uncontrolled diabetes at 25 weeks' gestation and 2) admission for uncontrolled hypertension and contractions at 31 weeks' gestation. The patient was readmitted at 32 weeks' gestation and remained confined to the hospital until her cesarean delivery at 33 weeks' gestation. The infant's weight was 5 pounds, 4 ounces, and his length was 17.75 inches. At the time of this report, he is a healthy, 7-year-old child.

Most nephrology practices have varied experience with successful pregnancies among patients receiving dialysis. Pinehurst Nephrology Associates in North Carolina has had four pregnancies resulting in live births in the last 25 years. Three of the newborns survived past infancy. Unfortunately, one of the pregnancies resulted in a neonate with multiple birth defects and maternal complications that led to the deaths of both the infant and the mother within 1 year of delivery. A.C. is the only patient who was dialyzed using the NxStage system during pregnancy; the remaining three individuals who were pregnant were all treated in-center with 4-hour treatments, 6 days/week.