A 38-year-old primigravida at 39+2 weeks is admitted for induction of labor. After 6 hours of oxytocin infusion, the cardiotocograph shows a pattern marked **C** — a gradual decrease in fetal heart rate with the nadir occurring 15–20 seconds AFTER the peak of each uterine contraction, with symmetric shallow decelerations (drop of ~25 bpm) and return to baseline between contractions. The baseline FHR variability remains normal. Which of the following is the MOST appropriate FIRST step in intrauterine resuscitation?