Having your doctor order prenatal tests may sometimes seem scary, but they provide information about your health and your baby’s health, and can detect problems before your baby is born. Among the tests you may receive, your doctor may suggest a nonstress test.

This noninvasive test doesn’t put any stress on your baby, which is where it gets the name. Although referred to as “nonstress,” it can be anything but — at least for you. This test checks for possible problems with your baby’s heartbeat and oxygen level, so it’s only normal to feel a measure of anxiety.

Here you can find out more about the process, including what to expect during the test and what the results mean so that you can feel a little less stress about the testing.

A nonstress test monitors your baby’s heart rate and response to movement.

You may start to feel your baby move as early as 16 weeks pregnant. As you move farther along you’ll find that your unborn baby becomes even more active. And as the baby moves, their fetal heartbeat increases. A strong, healthy heartbeat means that your baby is getting sufficient oxygen.

If your baby doesn’t move a lot, though, or if movements slow down, this may indicate that your baby isn’t getting enough oxygen. With any pregnancy, the goal is to maintain your health and your baby’s health. If your baby isn’t getting enough oxygen, you may need to deliver early.

Doctors recommend a nonstress test when they think there could be a problem with the baby or if you’re at risk for pregnancy complications. So this can be a period of heightened anxiety for you. Some women at high risk have several nonstress tests during their pregnancies, as often as once or twice a week, according to the Mayo Clinic.

The good news, though, is that a nonstress test doesn’t pose any risk to you or your baby.

Although a nonstress test is a common prenatal screening, not every expecting mother needs one. Only specific circumstances prompt doctors to advise testing.

You’ll likely need one if you have a high risk pregnancy, perhaps due to having a medical condition that puts stress on your baby. These include a blood disorder, kidney or heart disease, or a clotting disorder. You may also need one if you develop high blood pressure or diabetes before or during pregnancy.

Doctors may also suggest a nonstress test when a once active fetus begins to slow down or stops moving altogether.

Your baby’s movement should increase significantly as you get closer to your due date. Sometimes, it might feel as if your baby is doing somersaults or kickboxing in your belly. So naturally, less movement or not feeling anything at all can be frightening.

It’s important to mention any concerns about your baby’s movement to your doctor, including any changes in your baby’s pattern of movement.

Keep in mind, though, there’s no particular number of movements that must happen each day. Every baby is different, and so are their movement patterns. Even so, less activity can sometimes (not always) indicate a problem, hence the importance of a nonstress test to address any concerns.

Your doctor may also suggest a nonstress test under the following conditions:

  • You have a history of pregnancy complications.
  • You have low amniotic fluid.
  • You’re expecting multiples.
  • Your doctor suspects fetal growth problems.
  • You’re 2 weeks past your due date.

A nonstress test isn’t administered until the beginning of the third trimester, typically starting around 32 weeks but sometimes earlier in high risk pregnancies.

You don’t have to make special preparations for this test, nor do you have to visit a hospital. This test can take place in a doctor’s office.

A nonstress test is relatively short, lasting about 20 to 40 minutes. It’s typically performed by a nurse, with your OB-GYN or midwife interpreting the results.

You’ll have your blood pressure checked before the test and at different intervals throughout testing. Next, you’ll lie down on the exam table.

A nurse applies a special gel to your abdomen and then attaches a transducer around your stomach. This functions as an external fetal heart rate monitor to check your baby’s heartbeat. A uterine monitor is also applied to assess for any uterine contractions.

You may be asked to push a button every time you feel your baby move. You’ll probably receive a clicker or buzzer to hold in your hand. Each click or buzz sends movement information to a computer monitor.

If your baby is awake and active at the beginning of the test, your nonstress test may only last about 20 minutes. The test can take longer, though, if your baby is inactive or asleep. In which case, your nurse will first need to wake your baby.

To do so, they might place a noise-making device over your stomach. In addition, eating or drinking can wake up your baby and get them active.

Getting the results of a nonstress test can be particularly stressful. The good news is that you don’t have to wait several days for the results. You’ll know the outcome before you leave the office.

The results of a nonstress test are either reactive or nonreactive. With a reactive test, your baby’s heart rate and movement are both normal, which indicates that your baby is healthy and not under any stress. Your baby’s heart rate increased with movement as it should have.

On the other hand, test results can also be nonreactive. If so, your baby either didn’t meet the minimum number of movements required for the exam, or there wasn’t any change in your baby’s heart rate with movement.

Don’t fear the worst if your results are nonreactive. This can simply mean that your baby was still asleep or otherwise uncooperative during the test, thus explaining less movement.

If your nonstress test results are nonreactive, your doctor will likely recommend longer monitoring, possibly on the same day. Or, your doctor may order additional tests such as a biophysical profile. This monitors your baby’s breathing, body movements, and amniotic fluid level.

Based on the results of a second nonstress test and/or additional tests, your doctor may determine that your baby is indeed under stress. At this point, you’ll discuss whether it’s necessary to conduct further testing or if enough factors, including gestational age, support the decision to induce labor.

If you’re expecting multiples or have a high risk pregnancy, you may have multiple nonstress tests during your pregnancy, even when previous test results have been reactive. This way, your doctor can continue to monitor your baby’s health for the duration of your pregnancy.

A nonstress test isn’t stressful for your baby, but it can be for you. Even so, this test is necessary if you’re at high risk or if you’ve had previous complications.

Understandably, it’s hard to stay calm if your doctor has concerns about your baby, but try not to worry. The more information they have, the better able they are to keep you and your baby healthy.

Many women with nonreactive test results have delivered perfectly healthy babies, so don’t let one test result upset you. This test is just part of the picture of ensuring a healthy pregnancy for you and baby.