A 28-year-old G1P0 woman at 35 weeks gestation is in the obstetrical (OB) triage area with spontaneous rupture of membranes. The fetal hea rate baseline is 150 bpm with normal variability. There are accelerations seen, and numerous late decelerations noted. In an effo to improve oxygenation to the fetus, which of the following maneuvers would most likely help in this circumstance