Sherer D M, Abramowicz J S, D'Amico M L, Caverly C B, Woods J R
Department of Obstetrics and Gynecology, Strong Memorial Hospital, University of Rochester School of Medicine and Dentistry, NY 14642.
Am J Obstet Gynecol. 1991 Apr;164(4):1104-6. doi: 10.1016/0002-9378(91)90595-i.
Sixteen vibratory acoustic stimulations were performed in seven normal twin gestations with continuous simultaneous recordings of each fetal heart rate response. All stimulations led to immediate synchronous fetal heart rate accelerations in both fetuses. This is in contrast to coinciding, yet nonsynchronous, spontaneous fetal heart rate accelerations that occur naturally. This observation suggests that different mechanisms are responsible for spontaneous and evoked fetal movements in twin gestations.