A nationwide historical cohort study of all deliveries in Norway from 2012 through 2020 examined the incidence and risk factors for postpartum infections. Using linked registries, the investigators quantified diagnosis-coded postpartum infections and evaluated temporal trends. Among 516,874 deliveries, there were 5,942 cases (1.15%) coded as endometritis/puerperal sepsis (O85) and 8,833 cases (1.71%) coded as other postpartum infections (O86). The incidence of O85 increased significantly over time from 0.93% in 2012 to 1.38% in 2020 (test for trend, p < 0.001).
The authors conducted a historical cohort study by linking nationwide data from three sources: the Medical Birth Registry of Norway, the Norwegian Patient Registry, and Statistics Norway. Two outcome categories defined using ICD-10 codes were analysed: O85 (endometritis/puerperal sepsis) and O86 (other postpartum infections). The O85 code does not differentiate between endometritis and puerperal sepsis; the authors note that endometritis predominates within that category. Associations between exposures and outcomes were estimated as relative risks using log-binomial regression, and presented as adjusted relative risks (aRR) with 95% confidence intervals (CI).
Across the study period, postpartum infections were not rare. The abstract reports 1.15% for O85 and 1.71% for O86 of all deliveries. The increase in O85 incidence over time was statistically significant (from 0.93% to 1.38%, p < 0.001). The study also observed significant temporal increases in the incidences of chorioamnionitis/intrapartum infection and postpartum hemorrhage (both p < 0.001), conditions that may be related to postpartum infectious complications.
Delivery-related factors showed the strongest associations with both O85 and O86 after adjustment for covariates. The most prominent associations reported in the abstract were:
Emergency cesarean section: a strong association with both outcomes (aRRO85 2.8; 95% CI 2.6–3.0 and aRRO86 5.1; 95% CI 4.8–5.5).
Postpartum hemorrhage: also strongly associated with increased risk (aRRO85 3.2; 95% CI 2.9–3.4 and aRRO86 2.0; 95% CI 1.9–2.2).
These findings indicate that intrapartum and immediate post-delivery complications are key determinants of postpartum infectious morbidity in this population.
Several risk factors not directly tied to the mode or complications of delivery were also associated with both O85 and O86. The abstract reports increased adjusted risks for multifetal gestation, obesity, nulliparity, and maternal single status, with aRRs in the range of approximately 1.2–2.5. The abstract does not provide a full list of covariates or the exact adjusted estimates for each non-delivery factor beyond this range.
The study highlights a particularly strong association between intrapartum infection/chorioamnionitis and postpartum infections. Chorioamnionitis lies on a continuum with postpartum endometritis and is typically treated with intrapartum antibiotics that may be discontinued after delivery unless signs of infection persist. Reported adjusted relative risks were substantial: aRRO85 5.7 (95% CI 5.1–6.4) and aRRO86 3.2 (95% CI 2.9–3.6), indicating that intrapartum infection is a major predictor of postpartum infectious outcomes. The incidence of chorioamnionitis/intrapartum infection increased over the study period (p < 0.001), paralleling the rise in O85.
Based on the observed associations and temporal trends, the authors identify delivery-related factors—especially postpartum hemorrhage, emergency cesarean section, and chorioamnionitis/intrapartum infection—as potential targets for prevention strategies aimed at reducing postpartum infectious complications or preventing progression to more severe disease. The authors also call for revision of the coding system because the current O85 code conflates endometritis and puerperal sepsis, limiting surveillance precision and the ability to distinguish disease severity.
The provided text is the article abstract and therefore summarizes methods and major results but does not present full methodological detail. The abstract does not report specifics such as the complete list of covariates adjusted for in multivariable models, absolute risk differences, details of case validation, microbiology, timing of diagnosis, or subgroup analyses. Those details were not reported in the abstract and would require consultation of the full article for comprehensive appraisal.
In this large, nationwide Norwegian cohort, postpartum infections were relatively common and the coded incidence of endometritis/puerperal sepsis increased from 2012 to 2020. Delivery-related complications—most notably emergency cesarean section, postpartum hemorrhage, and chorioamnionitis/intrapartum infection—had the strongest adjusted associations with postpartum infection diagnoses. Non-delivery factors such as obesity, nulliparity, multifetal gestation, and single maternal status were also associated with elevated risks. The authors recommend focusing prevention efforts on delivery-related events and revising diagnostic coding to distinguish puerperal sepsis from endometritis to improve surveillance and targeting of interventions.
Note: The summary above is based on the article abstract; additional methodological and result details reported in the full text were not available in the provided source excerpt.