Pregnancy Outcomes in Women With Systemic Sclerosis Before and/or After Diagnosis and by Parity: A Swedish Population-Based Cohort Study.

Abstract

To assess risks of adverse pregnancy outcomes (APOs) in a contemporary cohort of women with systemic sclerosis (SSc) in relation to the timing of SSc diagnosis and by parity. From the nationwide Swedish Medical Birth Register, we assembled pregnancies with births in women with SSc and in comparator women from the general population (1998-2021). We classified pregnancies according to the timing of SSc diagnosis at birth: post-SSc (after SSc diagnosis [n = 94]) and pre-SSc (zero to three years [n = 39] or more than three years [n = 839] before diagnosis of SSc). We used regression models estimating relative risks (RRs) and odds ratios of APOs with 95% confidence intervals (CIs) in post-SSc and pre-SSc pregnancies, respectively. For post-SSc pregnancies, RRs of preeclampsia (3.8, 95% CI 1.8-7.8), preterm birth (3.3; 95% CI 1.8-6.1), and cesarean delivery (2.5; 95% CI 1.8-3.5) were increased. By contrast, there were no indications of increased proportions of maternal or neonatal death or stillbirth. Stratifying on parity, risks were considerably higher among primiparous post-SSc women (preeclampsia RR 7.5, 95% CI 3.5-16.1; preterm birth RR 5.1, 95% CI 2.5-10.5). We also noted increased odds of APOs in pre-SSc pregnancies, with the highest estimates in the zero to three years' pre-SSc pregnancies. Contemporary women with SSc displayed markedly increased risks of several APOs after SSc diagnosis; the risks of some APOs were already increased before diagnosis, particularly within three years. Our findings suggest that both preclinical and overt SSc have a substantial impact on pregnancy outcomes, especially in the first pregnancy, highlighting the importance of specialized care and close monitoring.