Relationship between placental weight and late‐onset circulatory collapse

Background Late‐onset circulatory collapse (LCC) is a serious complication in preterm infants and is increasing in Japan. The underlying pathophysiology is thought to be relative adrenal insufficiency and it is more likely to develop at a young gestational age (GA) and in low birthweight (BW) infants. BW to placental weight ratio (BPR) is an index of pregnancy outcomes and early neonatal morbidity. We aimed to analyze the relationship between LCC and potential predicting factors including BPR. Methods This retrospective study included 261 singletons born before 32 weeks of gestation between 2007 and 2017. Perinatal data, including the placental weight and BPR, were collected from medical records and were assessed for their relationship with LCC. Propensity score analysis was performed and matched factors were GA and BW. Results Sixty‐seven infants (25.7%) had LCC (median GA 27.4 weeks). GA and BW differed significantly between the LCC and non‐LCC groups (P