Fetal nonstress test (NTT), a test for pregnant women to check the baby's health

There are many medical tests aimed at pregnant women. One of them is a nonstress test that monitors the movement, heart rate, and contractions of the baby in the womb. This test is done when the date of birth is approaching or if the mother has complications during pregnancy. Read more about the nonstress test in this article.

What is a nonstress test?

The nonstress test (NST) is a simple and painless procedure performed during pregnancy to see how your baby is developing.

During the test, the doctor will monitor your baby's heart rate while it is resting and moving. Just like a normal human heart rate when actively moving, your baby's heart rate should also go up when he moves or kicks inside your womb.

The NST ensures that the baby in the womb is healthy and gets an adequate supply of oxygen.

This test procedure is very safe to do for both you and your baby. Nor will the doctor use medication to get your baby moving. So, the nonstress test will record all of your baby's activities naturally while in the womb.

Later, there may or may not be any movement of your baby during the test. However, this test does not aim to check the baby's movements, but rather to evaluate the reactivity of his heart rate.

Who should do this test?

NST is usually done if your pregnancy is past the due date, or in one / two months leading up to your due date if your pregnancy is at high risk. However, there are also several other conditions that require a pregnant woman to routinely perform the NST test, namely:

If you have gestational hypertension.
Your baby seems small or is not growing well.
Babies are less active than usual.
You have too much or too little amniotic fluid.
You have to do the procedure external cephalic version (changing the position of the breech baby), third trimester amniocentesis (ensuring if the baby's lungs are mature enough before birth or overcoming uterine infection).
Pregnancy has passed the due date.
Have had a history of miscarriage.
Your baby has been diagnosed by a team of doctors with a birth defect or abnormality and therefore requires intensive monitoring during pregnancy.
Have a medical problem that can harm your baby's health.

What is the procedure for this test?

You will be sitting, lying down, or on your side. In essence, the position is adjusted to your comfort, with two belts around the stomach. One belt functions to measure the baby's heart rate, while the other measures contractions.

When you feel the baby moving like a kick, you can press a button so that the doctor can see the development of the baby's heart rate, which changes as you move.

However, if your baby doesn't move during the test, it is likely that he is sleeping. If this is the case, the doctor will try to wake your baby by ringing the bell, moving the stomach or by using an acoustic stimulator to allow him to move. This test usually takes about 20 to 60 minutes.

Understand the results of the nonstress test for pregnant women

After the examination, the doctor will evaluate and diagnose the results. If your baby's heart beats fast while he's moving for at least 15 seconds on two separate occasions over a 20-minute span, the results are normal or "reactive."

This normal result indicates that your baby is doing well during the test. Usually doctors will recommend running more tests every week (or more often) until your baby is born.

Meanwhile, if your baby's heart doesn't beat faster when he's moving or your baby doesn't move after about 90 minutes, the test result is "no reaction". A test result that is not reactive does not necessarily indicate that something is wrong. The reason is that it only shows if the test you are taking provides inaccurate information, so you need to retest again an hour after, or perform other tests such as a biophysical profile and a contraction stress test.

However, the non-reactive results from the tests you've done could also indicate that your baby is not getting enough oxygen or is having problems with his placenta. If the doctor diagnoses your baby is not moving properly in the uterus, he or she may decide to induce labor.