Abstract
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.