A 32 year old woman at 42 weeks of gestation of her 2nd pregnancy presents in active labor. The baby is estimated to be 3.9 kg, with no anomalies.
Despite regular, strong contractions, progression through the second stage of labor is slow. A ventouse is applied, following which the head of the baby delivers easily, but then immediately retracts, with the baby's chin abutting the perineum.
Her 1st pregnancy was uncomplicated, with a 4.0 kg child delivered vaginally.