The innocuous little devices, such as the Sonoline B Fetal Doppler and the Neeva Baby Fetal Doppler, are inexpensive (that Sonoline model costs about $60)—and it can be tempting to use a device ...

Doppler velocimetry uses ultrasound to check blood flow in the umbilical cord or between the uterus and the placenta. If the blood supply is restricted, your baby can't get enough nutrients and ...