A 28-year-old primigravida at 39 weeks of gestation presents to the labour ward with regular uterine contractions. On examination, cervical dilation is 3 cm, and the fetal head is at −2 station. Fetal heart rate is 140 bpm with normal variability. After 6 hours of augmentation with oxytocin, cervical dilation remains 3 cm with no descent of the fetal head. Pelvic assessment suggests adequate pelvic dimensions. What is the most appropriate next step in management?