Association between activated partial thromboplastin time and septic shock in pregnant women: a retrospective cohort study

Maternal sepsis is a life-threatening infectious complication, with septic shock linked to high mortality. Coagulopathy is a key feature, but the association between activated partial thromboplastin time (APTT) and maternal septic shock remains unclear. This retrospective study included 1,631 pregnant women with infection admitted from January 2017 to March 2023. Based on admission APTT levels, patients were divided into three groups: <28 s (<i>n</i> = 697), 28-42 s (<i>n</i> = 915), and >42 s (<i>n</i> = 19). A U-shaped relationship was observed between APTT and septic shock risk. Compared to the reference group (APTT 28-42 s), the group with APTT >42 s had a higher incidence of septic shock (57.9% vs. 11.8%), with a multivariable-adjusted odds ratio (OR) of 3.85 (95% CI, 0.94-15.78, <i>p</i> = 0.061). APTT <28 s was also associated with increased risk (adjusted OR 1.5; 95% CI, 1.02-2.2; <i>p</i> = 0.04). Threshold analysis identified 27.564 s as a critical point. In addition, each 1-s increase in APTT raised shock risk by 8.7%. Monitoring APTT may facilitate risk assessment in obstetric sepsis.