Pregnancy-associated risk factors and incidence of systemic sclerosis in primiparous women: A nationwide population-based cohort study.

Abstract

To evaluate the pregnancy-related risk factors and incidence rate (IR) of systemic sclerosis (SSc) in primipara using the Health Insurance Review and Assessment database, covering all medical claims in South Korea. From the database, 2,260,952 primipara aged 18-49 years from 2008 to 2018 were identified. The patients were followed up after their index delivery until December 2019. A Cox proportional hazard analysis was performed to identify the association of pregnancy-related factors with SSc development. The SSc IR was 0.62 cases per 100,000 patient-years. Primipara had a higher risk of developing SSc after 3 years postpartum than in the first 3 years of delivery (OR = 1.98, 95% CI: 1.36-2.78, p < .001). A multivariate analysis showed that older age (35-49 years) (HR = 2.14, 95% CI: 1.05-4.35, p = .037) and a Caesarean section (CS) (HR = 1.86, 95% CI: 1.10-3.15, p = .021) are risk factors for SSc. At 3 years postpartum, CS (HR = 2.97, 95% CI: 1.39-6.32, p = .005) and a female infant (HR = 2.28, 95% CI: 1.11-4.71, p = .026) were associated with SSc development. Having a CS, late childbirth, and a female infant are the risk factors for SSc in primipara. This study establishes the IR of SSc in primipara.