Racial Differences and Factors Associated with Pregnancy in ESKD Patients on Dialysis in the United States

Significance Statement Pregnancy is not common in women on dialysis due to impaired fertility. Literature is scarce about pregnancy in women on dialysis in the United States. In this retrospective study, the authors examined the pregnancy rates and associated factors in 47,555 US women on dialysis from 2005 to 2013. They identified 2352 pregnancies, for a rate of 17.8 per thousand person years, a higher rate than seen in previous studies. Pregnancy rates were highest in Native American women followed by Hispanics, blacks, Asians, and whites. Younger age, hemodialysis as the dialysis modality, and ESKD caused by GN, vasculitis, neoplasm, and hypertension were associated with the higher likelihood of pregnancy. Patients with diabetes as the cause of ESKD had the lowest pregnancy rates. This study improves our understanding of pregnancy in women on dialysis, and can lead to better counseling and shared decision making. Background Pregnancy in women with ESKD undergoing dialysis is uncommon due to impaired fertility. Data on pregnancy in women on dialysis in the United States is scarce. Methods We evaluated a retrospective cohort of 47,555 women aged 15–44 years on dialysis between January 1, 2005 and December 31, 2013 using data from the United States Renal Data System with Medicare as primary payer. We calculated pregnancy rates and identified factors associated with pregnancy. Results In 47,555 women on dialysis, 2352 pregnancies were identified. Pregnancy rate was 17.8 per thousand person years (PTPY) with the highest rate in women aged 20–24 (40.9 PTPY). In the adjusted time-to-event analysis, a higher likelihood of pregnancy was seen in Native American (HR, 1.77; 95% CI, 1.33 to 2.36), Hispanic (HR, 1.51; 95% CI, 1.32 to 1.73), and black (HR, 1.33; 95% CI, 1.18 to 1.49) women than in white women. A higher rate of pregnancy was seen in women with ESKD due to malignancy (HR, 1.64; 95% CI, 1.27 to 2.12), GN (HR, 1.38; 95% CI, 1.21 to 1.58), hypertension (HR, 1.32; 95% CI, 1.16 to 1.51), and secondary GN/vasculitis (HR, 1.18; 95% CI, 1.02 to 1.37) than ESKD due to diabetes. A lower likelihood of pregnancy was seen among women on peritoneal dialysis than on hemodialysis (HR, 0.47; 95% CI, 0.41 to 0.55). Conclusions The pregnancy rate is higher in women on dialysis than previous reports indicate. A higher likelihood of pregnancy was associated with race/ethnicity, ESKD cause, and dialysis modality.