" .......... The technique appears to be a most reliable means of determining the presence of a live fetus; fetal life has been detected earlier and more consistently with the Doppler flow sensor than with fetal electrocardiograms. In one study of 25 pregnant women, in whom fetal heart rate could not be heard with the head stethoscope, the flow-meter elicited fetal flow signals with remarkable constancy as early as the 10th or 12th week (Fig 3, A). Fetal flow signals have been detected in more than 300 women after 12 weeks of gestation. In all cases where the fetal flow was not detected, the patient later delivered a stillborn infant.

The examination is quick and causes no discomfort to the patients; it can be repeated at intervals during pregnancy and delivery, whenever necessary or desirable. Expectant mothers have expressed relief at having heard fetal flow signals, particularly those who had doubts about their babies being alive.

The placental sound can frequently be heard (Fig 3, B) if the implantation is on the anterior surface of the uterus. Of interest, although of less clinical significance, is the use of the instrument for monitoring blood flow though the uterine artery and veins (Fig 3, C), and for detecting fetal movements that are undetectable by palpation. If the standard transducer is replaced with a fingertip transducer within a rubber glove, blood flow in the pelvic vascular channels can be detected......... "

Back to History of Ultrasound in Obstetrics and Gynecology.