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 < 0.001, respectively). The placental weight and BPR of the LCC group were significantly lower than those of the non-LCC group, while Z-score of BPR did not differ significantly between the groups. After propensity score matching, there was a significant difference in the incidence of severe intraventricular hemorrhage (grades III-IV; P = 0.042), but no differences in BPR and Z-score of BPR between the groups.

Conclusion: In the propensity score analysis matched for GA and BW, there was no significant difference in perinatal factors including BPR between the LCC and non-LCC groups, except for incidence of severe intraventricular hemorrhage.