The nurse is evaluating the fetal monitor tracing of the patient who is in active labor. Suddenly, the nurse sees the FHR drop from its baseline of 125 down to 80. The nurse repositions the mother, provides oxygen, increases intravenous fluids, and performs a vaginal exam. The cervix has not changed. Two minutes have passed, and the fetal heart rate remains in the 70s. What additional nursing measures should the nurse take?