[Fetal heart rate patterns in response to acoustic stimulation].

Fetal heart rate response to fetal acoustic stimulation (FAST) during the antepartum period after 25 weeks of gestational age was studied in 157 cases of normal pregnancy, 22 cases of fetal distress, 12 cases of SFD, 10 cases of fetal malformation, 9 cases of placental dysfunction, 4 cases of oligohydramnios, 12 cases of toxemia of pregnancy, and 15 cases of SLE. Five different types of response were observed: Type I through type V. 1. FAST was available to evaluate fetal well-being from 27 weeks of gestational age, although a nonstress test (NST) has been used after 31 weeks of gestational age. 2. Type IV was observed frequently in the case of coiling of the umbilical cord. 3. In acute fetal distress abnormality was detected by NST prior to FAST, but in latent fetal distress abnormality was detected by FAST prior to NST. 4. Cases classified as FAST types III and IV, which remained unchanged or deteriorated to III, IV or V were almost all characterized by poor fetal outcome.