Non-stress test in pregnancy: What it is, why it is done & what to expect

A non stress test pregnancy check helps your doctor know if your baby is doing well during advanced stages of pregnancy and labour. This non-invasive test looks at your baby’s heart rate and movement to make sure your baby is getting enough oxygen. Here’s all you need to know about non-stress tests in pregnancy.

What is a non-stress test (NST)? 

A non-stress test is a safe and painless test that checks your baby’s heart rate and how they react to movement. This test doesn’t put any stress on you or your fetus (baby), hence the ”non-stress” test. It typically involves two belly monitor bands. One for listening to your baby’s heartbeat and the other to monitor for any contractions. This helps your doctor know if your baby is healthy and getting enough oxygen. 

A non-stress test is essential during your third trimester (after 28 weeks of pregnancy). Especially, if there’re issues about your baby’s health or when you’ve gone past your due date. An NST can be optional during pregancy, your healthcare provider may not schedule any unless you show any indications. Or, if you’re at risk because of a symptom or disease like hypertension.  

Why do you get a non-stress test?

You may get a non-stress test if:

• Your pregnancy has gone past your due date (42 weeks or more) 
• You notice that your baby’s movement is not as frequent as before
• You have diabetes that is treated with medication, cardiovascular disease (heart disease) or any other condition that can affect your pregnancy
• You have high blood pressure pregnancy (gestational hypertension) or preeclampsia
• You have low amniotic fluid or high amniotic fluid
• You’ve experienced a birth complication before
• Your baby has been diagnosed with any birth defect (congenital disorder) which needs to be monitored
• You are pregnant for twins, triplets or more
• You have a Rh negative blood, while your baby is Rh positive
• Your fetus is really small for its gestational age or is not growing properly

Usually, your doctor will recommend this test when it’s necessary for your pregnancy.

When do you need to take the test?

As earlier mentioned, You’ll need to take a non-stress test during pregnancy if you’ve gone past your due date. Also, when it’s a month or two before your delivery if your pregnancy is high risk. A non-stress test is done weekly in your third trimester of pregnancy after 28 weeks, starting from 29 weeks to 40 weeks. 

This is because, before 28 weeks, your baby isn’t developed enough to respond reliably to the test. You may also need to take the test once a week or twice a week, with no more than 4 days' interval. Your doctor will let you know how many times you need it.

How long does a non-stress test take?

Non-stress tests take between 20-30 minutes or more. Sometimes, your baby may be asleep, your doctor can place a small buzzer or other noisemaker over your abdomen which isn’t harmful to wake your baby up. Your baby may also wake up if you take something sugary like a sugary drink (fruit juice) or a snack (oats, plain yogurts, nuts).

What should you expect during a pregnancy non-stress test?

During a pregnancy non-stress test, your doctor examines your baby’s heart rate and oxygen level. This test procedure is safe and there are no pins or needles involved. Your only requirement is to lay still on an examination table. Here’s how it works: 

• You’ll need to lie down on a reclined chair or exam table
• Your doctor may put a small amount of gel in your stomach
• Your doctor will attach two elastic belts with a sensor attached to it, on your belly
• You’ll be rerquired to click a button everytime you feel movement
• Your doctor will then move a monitor across your abdomen (belly) to detect your baby’s heart beat, after getting the needed information, your doctor or healthcare provider ends the test
• If your baby is not moving during the test, they may be asleep and they need to be awake for this test. Your doctor will place a safe vibrating device on your belly, this will make your baby wake up and be more active
• After the test, your doctor will remove the belt and discuss the result with you

What does the results mean?

Your non-stress test result can either be reactive or non-reactive. The results signify if your baby is getting enough oxygen or not. If they’re not. More tests will usually be required.  

Reactive  

For a nonstress test result to be reactive, your baby’s heart’s heart rate increases when you have a contraction or move. If it does, it means that your fetal (baby’s) heart rate is normal and reacts to movement. This is the expected outcome. It also has to react at least twice for 15 seconds per minute and within every 20 minutes.

Non reactive 

When a nonstress test result is non reactive, your baby’s heart rate will not increase when you have contraction or move. That doesn’t always mean that your baby isn’t healthy. Sometimes, a non reactive test result could be because your baby isn’t getting enough oxygen or was feeling sleepy when the result was being taken. Medications can also be another reason. However, if your non stress test continues to be non-reactive, intervention measures such as injections, induction or even a Ceaseran section can be employed to save the baby.

FAQs

How often do I need to have a non-stress test?

How often you have this test depends on your pregnancy and it also depends on any medical condition you have like diabetes and gestational hypertension. Your doctor may inform you to do it once a week or twice (every 4 days)

What are the risks of a nonstress test?

There are no risks for a non-stress test, it is completely free and safe for you and your baby

What happens if the fetus doesn’t move during a non-stress test (NST)?

Sometimes your fetus doesn’t move during a non-stress test because your baby is probably sleeping or about to sleep. It may also be because you are on medication. Your doctor may place a harmless buzzer or noisemaker over your belly to wake your baby up. Another alternative is that you may be advised to take something sugary that is safe for your baby like fruit juice or snacks.

Conclusion

Non-stress tests are a safe way of monitoring the well being of your baby or fetus during pregnancy. It doesn’t cause stress to you or your baby and it isn’t painful. It simply tells you and your doctor if your baby is fine or in distress. The result of this test shows if your baby is getting enough oxygen and if your baby’s heart rate is normal. Your result is either reactive which means your baby is getting enough oxygen and has a normal heart rate or non reactive which means you may need to carry out more tests to know if your baby is ok. You can talk to your healthcare provider if you are worried about your test result or have further questions.

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