A 32-year-old multiparous woman (G3P2) is admitted in active labor with cervical dilation of 6 cm. She has been in labor for 8 hours. Contractions are 2 in 10 minutes, each lasting 30 seconds. The partograph shows the cervical dilation point is approaching the alert line. Fetal heart rate is 135 bpm with good variability. What is the most appropriate next step in management?