Severe Maternal Morbidity and Long-Term Kidney Outcomes among Pregnant Women Receiving Maintenance Dialysis.

Abstract

In the United States, one in three pregnant women receiving maintenance dialysis experienced severe maternal morbidity from 2000 to 2020. History of severe maternal morbidity was associated with higher mortality and a longer time to kidney transplantation in the years following delivery. Pregnant women receiving maintenance dialysis are at high risk for adverse pregnancy outcomes. Little is known about their rates of severe maternal morbidity and the association of severe maternal morbidity with future kidney transplant wait times and mortality. This is a cohort study of women who gave birth while receiving maintenance dialysis from January 1, 2000, to December 31, 2019, as captured in the United States Renal Data System. Nonkidney severe maternal morbidity, defined by the US Centers for Disease Control and Prevention, was assessed from 4 weeks before birth to 6 weeks postpartum. Multivariable regression models examined risk factors independently associated with severe maternal morbidity. Multivariable Cox proportional hazards were stratified by the presence or absence of severe maternal morbidity to examine time to mortality, and, separately, the receipt of a kidney transplant. We identified 1082 births among 986 women who were receiving dialysis at the time of birth. In total, 332 women (34%) and 342 births (32%) experienced at least one nonkidney severe maternal morbidity. The most common severe maternal morbidity events were blood transfusion (16% of all births), pulmonary edema/acute heart failure (10%), sepsis (6%), and acute respiratory distress syndrome (5%). In multivariable analyses, risk factors independently associated with severe maternal morbidity included Black or other/unknown race, body mass index >35 kg/m 2 , and dialysis initiation within 1 year before giving birth. Patients who experienced severe maternal morbidity had a higher risk of mortality than those who did not (adjusted hazard ratio, 1.69; 95% confidence interval, 1.30 to 2.19) and were less likely to receive a kidney transplant than those who did not (adjusted subhazard ratio, 0.76; 95% confidence interval, 0.59 to 0.97). In the United States, one in three pregnant women receiving maintenance dialysis experienced severe maternal morbidity with risk factors that included recent dialysis initiation. In the following years, the history of severe maternal morbidity was associated with higher mortality and a longer time to kidney transplantation.