Preterm birth (PTB) remains a leading cause of neonatal morbidity and mortality worldwide. While conditions such as diabetes and hypertension have been linked to PTB, the contribution of multimorbidity, defined as the coexistence of two or more chronic conditions, has not been extensively quantified. This systematic review and meta-analysis evaluated the association between maternal multimorbidity and PTB risk. This systematic review and meta-analysis followed PRISMA 2020 guidelines and was prospectively registered in PROSPERO (CRD420251086046). PubMed, Scopus, Web of Science, and EBSCOhost were searched from database inception to November 2025 for observational studies examining the association between multimorbidity and PTB. Eligible studies included pregnant women with two or more chronic conditions compared with those without any chronic conditions. Study quality was assessed using the Newcastle–Ottawa Scale (NOS). Adjusted risk ratios (RRs) with 95% confidence intervals (CIs) were pooled using random-effects models, using retrieved RRs or converted Odds Ratios (ORs) to RRs. Analysis was performed separately for different gestational age thresholds ( 80%), there was no evidence of publication bias based on funnel plots or Egger’s test. Maternal multimorbidity is associated with a significantly increased risk of PTB, highlighting the importance of comprehensive preconception and antenatal care for women with multiple chronic conditions. However, the findings should be interpreted with caution due to substantial heterogeneity, variation in multimorbidity definitions, and the observational design of the included studies. Further large-scale, high-quality prospective research using standardized definitions of multimorbidity and PTB is needed to strengthen the evidence base and clarify causal pathways. PROSPERO: CRD420251086046.
Mastrou et al. (Fri,) studied this question.