Transperineal Ultrasound Assessment Of Fetal Head Elevation By Maneuvers Used For Managing Umbilical Cord Prolapse

Objective To assess objectively the degree of fetal head elevation achieved by different maneuvers commonly used for managing umbilical cord prolapse.Methods This was a prospective observational study of pregnant women at term before elective Cesarean delivery. A baseline assessment of fetal head station was performed with the woman in the supine position, using transperineal ultrasound for measuring the parasagittal angle of progression (psAOP), head-symphysis distance (HSD) and head-perineum distance (HPD). The ultrasonographic measurements of fetal head station were repeated during different maneuvers, including elevation of the maternal buttocks using a wedge, knee-chest position, Trendelenburg position with a 15 degrees tilt and filling the maternal urinary bladder with 100 mL, 300mL and 500mL of normal saline. The measurements obtained during the maneuvers were compared with the baseline measurements.Results Twenty pregnant women scheduled for elective Cesarean section at term were included in the study. When compared with baseline (median psAOP, 103.6 degrees), the knee-chest position gave the strongest elevation effect, with the greatest reduction in psAOP (psAOP, 80.7 degrees; P<0.001), followed by filling the bladder with 500mL (psAOP, 89.9 degrees; P<0.001) and 300mL (psAOP, 94.4 degrees; P<0.001) of normal saline. Filling the maternal bladder with 100mL of normal saline (psAOP, 96.1 degrees; P=0.001), the Trendelenburg position (psAOP, 96.8 degrees; P=0.014) and elevating the maternal buttocks (psAOP, 98.3 degrees; P=0.033) gave modest elevation effects. Similar findings were reported for HSD and HPD. The fetal head elevation effects of the knee-chest position, Trendelenburg position and elevation of the maternal buttocks were independent of the initial fetal head station, but that of bladder filling was greater when the initial head station was low.Conclusions To elevate the fetal presenting part, the knee-chest position provides the best effect, followed by filling the maternal urinary bladder with 500mL then 300mL of fluid, respectively. Filling the bladder with 100mL of fluid, the Trendelenburg position and elevation of the maternal buttocks have modest effects. (C) 2020 International Society of Ultrasound in Obstetrics and Gynecology.