The fetal recoil test.

A reassuring fetal recoil test has positive and negative predictive values of 98% and 8%, respectively, for a reactive nonstress test (sensitivity 89%, specificity 33%). Among 21 of 30 subjects in whom recoil was present immediately before delivery, none had umbilical arterial pH values < or = 7.20 versus 5 of 9 (56%) with nonreassuring recoil (p = 0.005). We concluded that a reassuring fetal recoil test is a reliable marker for fetal well-being.