FCOG-1172

A 30-year-old G2P1 woman presented to the maternity unit, in labour at 38 weeks gestation. During her previous pregnancy she delivered a healthy baby through caesarean section. The current pregnancy had been uneventful without any remarkable problems in antenatal visits except for the first trimester nausea and vomiting. On arrival, she had a cervical dilation of 4 cm and the fetal head was at -1 station. After 5 hours, the cervical length and fetal head station are still the same despite regular uterine contractions. Suddenly, there is a sudden gush of blood, which is approximately 1000 ml and the fetal heart rate have dropped to 80 bpm on CTG. Which of the following could be the most likely cause for this presentation?