Simultaneous nonstress fetal heart rate testing in twin pregnancy

Twenty-four sets of twins in the third trimester of pregnancy underwent 120 simultaneously recorded nonstress tests (NSTs). Synchronous patterns of fetal heart rate alterations occurred in 58% of the cases and were associated with single placentas and small weight differences between twins. Reactive NSTs were frequent (77%) and, when they occurred within 1 week of delivery, conferred a good prognosis, ie, no perinatal deaths and low morbidity. Nonreactive NSTs were associated with both fetal deaths and a perinatal morbidity of 28%. Simultaneous NSTs for twins are technically feasible in the third trimester. They confer a reliable prognosis when reactive; nonreactive tests are less specific and require further investigation.