Parity as a predictor of functional limitations and sick leave in pregnancy-related low back and pelvic pain: a Danish cross-sectional study

Background: Parity has been reported as a risk factor for pregnancy-related low back and pelvic girdle pain (LBPP), but evidence is often based on retrospective self-report data from late pregnancy or the postpartum period. Less is known about whether parity influences pain severity once LBPP is present, and how it affects daily functioning and work participation. Aim: To compare nulliparous and parous participants with clinically validated LBPP at mid- and later pregnancy, focusing on pain severity, functional limitations, and sick leave. Methods: In a cross-sectional design, 222 pregnant women with LBPP completed questionnaires at routine antenatal consultations in gestational weeks 18 and 28. Pain was assessed on six numerical rating scales (0–10), and functional limitations on ten daily activities. Pain diagnoses were validated through clinical examination. Linear and ordinal regression models with robust standard errors were fitted, adjusting for age, job demands, and prior pain. Multiplicity was controlled using false discovery rate (FDR) correction. Findings: Parous women reported higher pain scores across consultations, however differences were small and non-significant after FDR correction. In contrast, they consistently reported greater functional limitations in more demanding daily activities, particularly later in pregnancy. Parous participants were also substantially more likely to be on sick leave. This association remained robust after adjustment for covariates. Conclusions: Among women with clinically defined LBPP, parity was not a strong predictor of pain severity but was associated with greater functional limitations and sick leave. These findings suggest that parity may be particularly relevant for the consequences of LBPP.