Fetal acoustic stimulation as an adjunct to external cephalic version.

OBJECTIVE: To evaluate fetal acoustic stimulation (FAS) as an adjunct to external cephalic version in a midline fetal spine presentation.

STUDY DESIGN: Breech presentation in a woman presenting for attempted version at 37 weeks' gestation with a fetus in a midline position and the spine anterior is difficult to convert to a vertex. An evaluation of FAS to assist in repositioning the fetus in a more spine lateral position was carried out. Patients with a failed version attempt and a midline breech presentation were enrolled in the study. The patient served as her own control. If that attempt failed, an electrolarynx device was used to produce a one- to three-second stimulus, and then another version attempt was made.

RESULTS: Sixteen patients were enrolled. Prior to FAS, 0/16 fetuses were successfully turned. FAS altered the position in 100% of patients from spine midline to lateral. After FAS, 15/16 (94%) were successfully converted to vertex presentation. The one patient whose fetus failed to convert also failed her second version attempt (P < .0005).

CONCLUSION: FAS may improve the opportunity for successful external cephalic version in the properly selected candidate with a fetus in a midline position with the spine anterior.