Clinical and subclinical chorioamnionitis in preterm births and late miscarriages: a prospective cohort study

Background: Preterm birth is the leading cause of neonatal mortality worldwide and is associated with long-term neurodevelopmental morbidity. Nearly 40-50% of preterm births and up to two-thirds of late miscarriages are infection-related. Chorioamnionitis, a common intrauterine infection, significantly contributes to early-onset neonatal sepsis and maternal complications. Clinical chorioamnionitis is diagnosed using Gibb’s criteria, whereas subclinical chorioamnionitis is confirmed only on histopathology and is more prevalent. This study aimed to determine the incidence of clinical and subclinical chorioamnionitis in spontaneous preterm deliveries, preterm premature rupture of membranes (PPROM) and late miscarriages. Methods: This prospective cohort study was conducted over one year at a tertiary care center. One hundred antenatal women between 16 and 36+6 weeks with preterm labour, PPROM, or late miscarriage were enrolled. Clinical features, laboratory parameters like white blood cell count (WBC), C-reactive protein (CRP), high vaginal swab, urine culture, and neonatal outcomes were recorded. Placental tissues were examined for histopathology, and neonatal sepsis, if present, was documented. Results: Fifty seven percent had PPROM, 42% spontaneous preterm labour, and 1% late miscarriage. Elevated WBC (>15,000) was seen in 38%, and 52% had CRP levels twice normal. Positive high vaginal swabs were noted in 39%. 10% had positive urine culture. Incidence of clinical, microbiological, and histopathological chorioamnionitis was 7%, 11%, and 34%, respectively. Four cases met criteria for triple I, and six neonates developed early-onset sepsis. Conclusions: Clinical criteria showed high specificity but low sensitivity, missing 79.4% of histological cases. WBC and CRP had moderate predictive value. Early diagnosis remains crucial to balance prematurity risks against infection-related morbidity. Better diagnostic tools are needed to identify underlying intrauterine inflammation.