The fetal heart is monitored after the turn attempt, usually in the context of an institutional protocol.

Doppler: A machine that uses ultrasound to detect the fetal heart.

Typically, a concentrated salt solution is injected directly into the fetal heart using ultrasound to guide the needle.

The fetal heart begins to beat at approximately the same rate as the mother's, which is typically 80 to 85 bpm.

No one can tell you what it feels like to hear silence where the fetal heart is supposed to be.

But to a pediatric cardiologist, the device is a window into the inner workings of a tiny fetal heart.

Essentially, the procedure, which has become increasingly refined over the last decade, produces a highly sophisticated ultrasound image of the fetal heart.

An examining physician listened for fetal heart sounds, but could find none.

More controversial is replacing the fetal heart rate monitor with simply listening to the fetus's heart every 15 minutes.

More recently he devoted his research to the fetal heart.