Patients with autoimmune skin diseases are at increased risk of adverse pregnancy outcomes

BACKGROUND: Increased rates of adverse pregnancy outcomes have been reported in association with rheumatologic diseases such as systemic lupus erythematosus, rheumatoid arthritis, dermatomyositis. However, little is known about pregnancy outcomes in patients with autoimmune skin diseases. OBJECTIVE: This study aimed to determine the frequency of adverse pregnancy outcomes in patients with autoimmune skin diseases. We hypothesized that similar to rheumatic diseases, the rate of adverse pregnancy outcomes in patients with autoimmune skin diseases would be higher than the general population. STUDY DESIGN: This is a case control study using the TriNetX US Collaborative Network, which is a database of electronic medical records of >95 million patients seen at 57 healthcare organizations in the United States. All pregnant women between the ages of 15 and 44 years who were seen at a healthcare organization between January 1, 2016 and December 31, 2021 were included. Participants with autoimmune skin disease were matched to healthy controls and controls with systemic rheumatologic conditions (systemic lupus erythematosus or rheumatoid arthritis). For both the autoimmune skin disease and healthy control groups, those with systemic rheumatologic condition or hidradenitis suppurativa were excluded. The primary outcomes were adverse pregnancy outcomes defined as spontaneous abortion, gestational hypertension, preeclampsia or eclampsia, gestational diabetes mellitus, intrauterine growth restriction, preterm premature rupture of membranes, preterm birth, and stillbirth. Patients with autoimmune skin diseases and controls were 1:1 propensity score-matched by age, race, ethnicity, comorbidities, obesity, and substance use. For each outcome, odds ratio with a 95% confidence interval was calculated. RESULTS: A total of 2788 patients with autoimmune skin diseases were matched to 2788 healthy controls. Patients with autoimmune skin diseases were at a higher risk of spontaneous abortions than controls (odds ratio, 1.54; 95% confidence interval, 1.36–1.75; P<.001). Compared with patients with systemic lupus erythematosus, patients with autoimmune skin diseases were at lower risk of having infants with intrauterine growth restriction (odds ratio, 0.59; 95% confidence interval, 0.4–0.87; P=.01), preterm birth (odds ratio, 0.68; 95% confidence interval, 0.47–0.98; P=.04), and stillbirth (odds ratio, 0.50; 95% confidence interval, 0.25–0.97; P=.04). The differences in adverse pregnancy outcomes between patients with autoimmune skin diseases and those with rheumatoid arthritis were not statistically significant. CONCLUSION: Patients with autoimmune skin diseases are at a higher risk of spontaneous abortions than patients without autoimmune skin diseases. When analyzed by each autoimmune skin disease, patients with cutaneous lupus erythematosus or vitiligo remained at increased risk of spontaneous abortions compared with patients without autoimmune skin diseases. Patients with autoimmune skin diseases have similar risks of adverse pregnancy outcomes as patients with rheumatoid arthritis, but lower risks than patients with systemic lupus erythematosus.