A 37-year-old G7P6 presents at 38 weeks gestation of twins,…

A 37-year-old G7P6 presents at 38 weeks gestation of twins, for induction of labor. She is started on oxytocin, but labor progresses slowly and she is only dilated to 4 cm after 15 hours. The fetuses develop tachycardia and the woman is diagnosed with chorioamnionitis and started on antibiotics. Seven hours later the twins are born and there is hemorrhage with continual blood flowing out the vagina. What is the most likely cause of this?