Soru

A nulliparous patient at $38$ weeks and $5$ days gestation is monitored on the labor ward after presenting with painful uterine contractions. Her prenatal course was unremarkable. Current maternal vital signs are temperature $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), blood pressure $122/80$ mm Hg, and pulse $88$/min. Pelvic examination demonstrates a cervix that is $6$ cm dilated and $90\%$ effaced, with the fetal vertex at $0$ station. The amniotic membranes ruptured spontaneously one hour ago. Uterine contractions are palpable every $3$ minutes. The continuous fetal heart rate monitor displays a baseline of $140$/min with moderate variability. Throughout the last $20$ minutes, the tracing reveals recurrent, abrupt decreases in the fetal heart rate to $85$/min that last for approximately $40$ seconds before abruptly returning to the baseline. The nadirs of these decelerations have no consistent temporal relationship to the uterine contractions. Which of the following is the most appropriate initial step in the management of this patient?