The American Congress of Obstetricians and Gynecologists have developed guidelines of what is considered a normal fetal heart rate and an abnormal fetal heart rate. Fetal heart rate is often referred to as FHR. Your doctor will monitor your baby's FHR for sudden changes or serious conditions.
The guidelines set by for a normal fetal heart rate should range between 120 and 160 beats per minute, or bpm. Earlier in pregnancy, around week 5, the baby's heart rate will closely match your heart rate, which is around 85 bpm, according to KidsHealth.org. Your baby's heart rate will continue to accelerate until you are just over two months pregnant when your baby's heart rate reaches 170 to 200 bpm. The fetal heart rate acceleration only lasts a short time at the beginning of your ninth week of pregnancy. Once the FHR reaches this accelerated heart rate, it begins to decline to the normal FHR range. Both genders have similar FHR ranges.
Your doctor can identify your baby's FHR as soon as the fourth week of pregnancy, according to the American Congress of Obstetricians and Gynecologists. Your physician may use a special device called a doppler to hear the baby's heartbeat around your eight week or pregnancy, or later. The doctor will place the microphone-like portion of the doppler on your abdomen and the sound will come out of the other end of the machine, which looks similar to a small radio. Another method your doctor may use to hear the baby's heartbeat is a fetoscope. A fetoscope is similar to a regular stethoscope, which a doctor places into his ears to listen to your heartbeat.
It's important that your obstetrician monitors FHR regularly throughout your pregnancy. A fetus can experience bradycardia or tachycardia. Bradycardia is a slower than normal heartbeat. For fetuses, bradycardia is a heart rate less than 120 bpm, according to the American Congress of Obstetricians and Gynecologists. Tachycardia is an abnormally fast heart rate. A fetus suffering from tachycardia will experience heart rates greater than 160 bpm, but it is considered severe if the fetal heart rate exceeds 180 bpm, according to the American Congress of Obstetricians and Gynecologists.
Your baby's fetal heart rate can increase or decrease during labor and delivery. The FHR can vary during the birthing process due to uterine contractions. When you go into labor, your doctor may place an electronic fetal heart rate monitoring device over your abdomen to constantly monitor your baby's heart rate to decrease the risk of complications. The electronic fetal heart rate monitor will print out the reading on a narrow sheet of paper, similar to how a lie detector machine prints out a reading.
If you notice that your baby becomes significantly less active once you are feeling fetal movement, make an appointment with your doctor and ask him to check your baby's heart rate. You may also hear that if the heart beat is on the slower side, you're having a boy or vice versa. This is not true, according to KidsHealth.org. Do not rely on the FHR to determine gender as boys and girls have similar heart rates.