Fetal Heart Rate Monitoring: What Does It Tell?

A fetal Doppler test normally takes place during your second trimester (weeks 13 to 28 of pregnancy). Some manufacturers of at-home fetal Dopplers say you may be able to hear your baby’s heartbeat as early as 8-12 weeks of pregnancy. But professional sonographers say that they wouldn’t try to listen to a baby’s heartbeat before 13 weeks because your womb is in your pelvis during the first trimester, and so the device won’t work correctly. Some at-home devices say not to use it before 16 weeks.

If you’re trying to hear your baby’s heartbeat at home, it may be best to first wait for your doctor to check it during one of your prenatal checkups. This is especially true if you’ve been pregnant for less than 12 weeks, to avoid undue concern. It’s a good idea to talk to your doctor before you buy an at-home fetal Doppler. They can talk to you about the benefits and risks involved with using these devices.

Internal fetal monitoring

Once your water breaks and your cervix opens to prepare for birth, the doctor can run a wire called an electrode through it and into your womb. The wire attaches to your baby’s head and connects to a monitor. This gives a better reading than listening to your baby’s heartbeat from the outside.

4. Fetal Heart Rate Monitoring Procedure

Fetal heart rate monitoring could happen in your doctor’s office or at the hospital. The procedure will depend on what type of monitoring you’ll have.

External fetal heart rate monitoring procedure

• Your doctor or technician will ask you to undress and lie down on an exam table or labor bed.
• They'll spread clear gel on your belly.
• Your doctor will press a gadget called a Doppler transducer to your belly and move it around.
• You’ll hear the sound of your baby’s heartbeat.
• If your doctor wants to measure the heartbeat continuously, they’ll use a wide belt to hold the transducer in place.
• Your doctor will record the fetal heart rate. You may see it on a computer screen.

Internal fetal heart rate monitoring procedure

• You’ll be asked to undress and lie down.
• You’ll put your feet and legs in supports, like you’re getting a vaginal exam.
• The doctor will check to see if your cervix is dilated.
• If your water hasn’t broken, the doctor may break it.
• The doctor will feel for your baby’s head.
• They'll put a thin tube (catheter) with a small wire at the end into your vagina.
• The doctor will put the wire on your baby’s scalp and remove the catheter.
• Once it’s connected to a cable, the wire will record your baby’s heartbeat until a doctor removes it or your baby is born.