Which of the following maneuvers is most commonly used first to relieve shoulder dystocia during childbirth?

A. McRoberts maneuver. This technique involves hyperflexing the mother's legs tightly against her abdomen to flatten the sacrum and rotate the symphysis pubis cephalad. It is the gold standard first-line intervention because it is non-invasive and effectively increases the pelvic diameter. This maneuver often provides enough space for the impacted fetal shoulder to pass under the pelvic bone. B. Zavanelli maneuver. This is a highly invasive, last-resort procedure that involves pushing the fetal head back into the uterus for an emergency cesarean section. It is only attempted when all other maneuvers, such as McRoberts and suprapubic pressure, have failed to resolve the dystocia. It carries a extremely high risk of maternal and fetal morbidity and mortality. C. Fundal pressure. Applying pressure to the top of the uterus is strictly contraindicated during a shoulder dystocia. Fundal pressure can further wedge the fetal shoulder against the symphysis pubis, increasing the risk of uterine rupture or brachial plexus injury. Suprapubic pressure, applied just above the pubic bone, is the correct technique to dislodge the shoulder. D. Episiotomy. An episiotomy is a surgical incision of the perineum that expands the vaginal opening but does not resolve the underlying bone-on-bone impaction of the shoulder. While it may provide more room for the provider's hands to perform internal maneuvers, it is not the primary corrective action. The problem in shoulder dystocia is the pelvic architecture, not the soft tissue.