Rounded intraplacental hematoma - A high risk placental lesion as illustrated by a prospective study of 26 consecutive cases

Background: A rounded intraplacental hematoma (RIH) is a recently delineated placental lesion. Following the observation of two cases of RIH in placentas associated with stillbirth in 2012, we postulated that RIHs were associated with a higher risk obstetric phenotype when compared to other lesions characteristic of maternal vascular malperfusion (MVM). We aimed to investigate this further by reviewing the associated maternal and fetal characteristics in a series of prospectively identified cases. Methods: Pregnancies where a RIH was identified on placental examination were prospectively collected from February 2014-July 2016. Comparison was made with pregnancies with placental evidence of MVM but without RIH. Results: 26 placentas with a RIH were identified and 26 placentas with MVM were selected for comparison. There was a statistically significantly increased incidence of stillbirth in the RIH group as compared with the MVM-only group (p = 0.022). Also, pregnancies with RIHs had a lower maternal age (p = 0.041), decreased incidence of antenatally diagnosed growth restriction (p = 0.023), a trend to increased incidence of clinical abruption (p = 0.051) and heavier mean infant birthweight (p = 0.034). Both groups had a high incidence of pre-eclampsia, Caesarean section and preterm delivery when compared with the general population. Discussion: This is the first study to prospectively identify and collect RIHs using standardised pathological criteria and more than doubles the number of reported cases to date. We present 2 comparable, high-risk cohorts but with a significantly increased incidence of stillbirth in those in which RIHs were seen. Further study of these lesions is justified with an emphasis on the potential for antenatal detection using ultrasound evaluation of placental texture.