Objective To investigate structural changes in the uteroplacental blood vessels in association with placental abruption.
Design Prospective descriptive study.
Subjects 18 women with clinical evidence of severe placental abruption delivered by caesarean section.
Interventions Placental bed biopsies were obtained at caesarean section and studied histologically.
Results Six specimens did not include trophoblast in the myometrium and were therefore not representative of the placental bed. Of the 12 representative specimens, seven demonstrated absence of physiological transformation of the utero-placental arteries (four of these were from hypertensive patients). Four biopsies showed abnormal vascular structures deep in the myometrium. One of these abnormal vessels included a fresh plug and extensive surrounding intramyometrial haemorrhage.
Conclusions Vascular malformations in association with placental abruption may be the result of trophoblastic invasion and could be the site of vessel rupture. Further descriptive and comparative studies are needed.