Pregnancy Outcomes in a Diverse US Lupus Cohort

Although the population of patients with systemic lupus erythematosus (SLE) is racially and ethnically diverse, many study populations are homogeneous. Further, data are often lacking on critical factors, such as antiphospholipid antibodies (aPLs). We investigated live birth rates in patients with SLE at Kaiser Permanente Northern California, including race and ethnicity and aPL data.

Electronic health records of pregnancies with outcomes observed from 2011 to 2020 were identified among patients with SLE. Prevalent SLE was defined as two or more International Classification of Diseases-coded visits seven or more days apart before the last menstrual period. We summarized patient characteristics, medication orders, health care use, and medication use. Pregnancy outcomes (live birth, stillbirth, spontaneous abortion, ectopic pregnancy, and molar pregnancy) were presented overall and stratified by race and ethnicity, aPL status, and nephritis history.

We identified 657 pregnancies among 453 patients with SLE. The cohort was diverse, reflecting the Northern California population (27% Asian, 26% Hispanic, 26% Non-Hispanic White, 13% Non-Hispanic Black, 5% multiracial, and approximately 2% Pacific Islander and Native American). Approximately 74% of observed pregnancies ended in live birth, 23% resulted in spontaneous abortion, 2% were ectopic or molar pregnancies, and <1% were stillbirths. There was limited variability in live births by race and ethnic group (72%-79%), aPL status (69.5%-77%), and nephritis history (71%-75%).

Our findings are consistent with previous studies; however, some methodologic differences may yield a range of live birth rates. We found that approximately 74% of pregnancies in patients with SLE ended in live birth, with modest variability in spontaneous abortion by race and ethnicity, nephritis history, and aPL status.