Creating a placental inflammatory composite index that has a high prognostic relevance to child morbidity

Aim Selecting pathologic measures of placental inflammation that affect pregnancy and childhood health is largely empirical. We aimed to systematically select several core inflammation‐related placental measures to construct a novel placental inflammatory evaluation criterion with a high prognostic relevance to child morbidity. Methods We used data from the US Collaborative Perinatal Project (1959–1976), a longitudinal birth cohort study that recruited women during pregnancy and followed the children until 7 years of age. Bootstrap resampling, least absolute shrinkage and selection operator, and receiver–operator curve were used to select placental pathologic measures that were closely related to child morbidity to form a placental inflammatory composite index. Results Twenty‐six candidate placental inflammation‐related measures were ranked based on their close association with adverse neonatal outcomes. The top five placental measures were: (i) neutrophilic infiltration in umbilical artery; (ii) placental weight–birthweight ratio; (iii) necrosis in decidua capsularis ; (iv) bacterial colony in epithelium of amnion; and (v) opacity of membranes and fetal surface. Several composite indexes were constructed. A five‐measure composite index that had the highest prognostic relevance was chosen. Compared with subjects without any of the five abnormal measures, those with any lesion ranging from 1 to 5 had a 1.2‐ to 4.6‐fold risk of adverse child outcomes, respectively. Conclusion Our composite index is simple, evidence‐based, and has predictive value for child morbidity. It may be used as a novel placental inflammatory evaluation criterion.