Nonstress test (NST) - Definition & Explanation for Mothers

Table of Contents

Definition

A Nonstress Test (NST) is a type of prenatal test used to monitor the baby’s heart rate and movement. It is called non-stress because no stress is placed on the fetus during the test. This test helps to evaluate the baby’s health status, particularly indicating if the baby is getting enough oxygen.

Key Takeaways

A Nonstress Test (NST) is a simple, noninvasive procedure carried out during pregnancy. It evaluates the baby’s health by monitoring if their heart rate increases appropriately during activity, indicating good oxygen supply.
This test is often recommended for high-risk pregnancies, or if the baby is not moving as regularly as usual, is overdue, or in cases where the practitioner wants to ensure the health of the baby closer to the due date.
Usually, an NST is done in the third trimester of pregnancy, but can also be conducted earlier. It is a safe procedure with no known risks to either the mother or unborn child.

Importance

The term “Nonstress Test (NST)” is important in motherhood because it is a common prenatal test used to check on a baby’s health.

The test monitors the baby’s heartbeat, specifically looking for any increase in the baby’s heart rate when the baby moves, as this is usually a sign that the baby is doing well.

It helps medical professionals assess the well-being of the unborn child, especially in high-risk pregnancies or in situations where the baby is not moving as often as expected.

This test offers valuable information about the baby’s oxygen supply and can help determine if the baby is under any stress, assisting doctors in taking necessary steps towards the baby’s health and safety.

Therefore, the nonstress test plays a crucial role in ensuring the health and well-being of the baby during pregnancy.

Explanation

The primary purpose of a Nonstress Test (NST) during pregnancy is to ensure that the fetus is receiving adequate oxygen in the womb, which signals good health. It is called a ‘nonstress’ test because it brings forth no stress or harm to both the mother and her unborn child.

This test helps in monitoring the baby’s heart rate and how it responds to the baby’s movements, typically in the third trimester. Regular heart rate accelerations often indicate that the baby is doing well and that its central nervous system is regulating the heart rate appropriately.

The NST is generally used when a healthcare provider suspects that the baby might not be doing as well as they would hope for inside the womb. This can include instances such as if the mother has medical complications, if the baby has stopped moving as frequently as before, or if the baby is not growing as expected.

Sometimes, NST will also be performed in the case of multiple pregnancies (twins, triplets etc.), post-term pregnancies, or even when the mother is past her due date. The results can provide doctors critical information, thereby aiding them to decide if the baby needs to be delivered immediately or continue the pregnancy, ensuring the best outcomes for both the mother and baby.

Examples of Nonstress test (NST)

Example 1: A pregnant woman who is carrying twins is in her third trimester. Her doctor decided to perform a nonstress test twice a week to carefully monitor the babies’ health. In each session, the doctor places two belts with sensors around her abdomen, one that measures the fetal heart rate and another that measures contraction occurrence. Throughout the test, the doctor looks for heart rate changes as the babies move, confirming they are both healthy.

Example 2: A 38-year-old pregnant woman past her due date undergoes a nonstress test as part of evaluating the health of her baby because overdue babies can sometimes have problems. During the NST, the mother-to-be experiences mild contractions. The baby’s heart rate accelerates with each contraction which indicates a healthy stress response and ensures the baby is doing well.

Example 3: A woman experiencing a high-risk pregnancy due to gestational diabetes undergoes regular nonstress tests each week starting from her 32nd week of pregnancy. The NST helps her doctor to identify any signs of fetal distress or complications related to her diabetes. In this scenario, the NST offers reassurance that the baby is doing well inside the womb, despite the mother’s health condition.

Frequently Asked Questions About Nonstress Test (NST)

What is a Nonstress Test (NST)?

A Nonstress Test (NST) is a type of test performed during pregnancy. This test measures the heart rate of the fetus in response to its own movements. This test is simple, noninvasive, and gives valuable information about the health of the baby.

Why is a Nonstress Test (NST) performed?

The NST is usually performed in pregnancies over 28 weeks gestation. It helps identify if the fetus is not getting enough oxygen due to problems with the placenta or umbilical cord. The test is also used if the pregnancy is high-risk because of complications like gestational diabetes or high blood pressure.

How is a Nonstress Test (NST) performed?

During a NST, two belts with sensors are placed around the mother’s abdomen, one tracks the baby’s heart rate and movement, the other measures contractions in the uterus. The test usually takes 20 to 30 minutes, during which the baby’s heart rate should increase with each move the baby makes.

What does a ‘reactive’ or ‘non-reactive’ result mean in a NST?

A ‘reactive’ result indicates that the baby’s heart rate is rising as expected when the baby moves. This is a good sign and suggests that the baby is getting enough oxygen. A ‘non-reactive’ result means the baby’s heart rate is not elevating during movement, and more tests may be required for further evaluation.

Is the Nonstress Test (NST) safe?

Yes, the nonstress test is safe. The test uses sound waves and does not involve any risks for the mother or baby. However, the test results need to be interpreted cautiously as there may be multiple factors like the baby’s sleep cycles or movements that may affect the results.

Related Motherhood Terms

Fetal heart rate
High-risk pregnancy
Braxton Hicks contractions
Biophysical profile (BPP)
Obstetric ultrasound

Sources for More Information

Mayo Clinic – A trusted source for medical information, covering various medical topics including maternity and motherhood.
Webmd – An online leader in health information services for consumers, physicians, healthcare professionals, employers and health plans.
Healthline – A health information site with a mission to make the people of the world healthier through the power of information.
American Pregnancy Association – Promotes pregnancy wellness and education for mothers-to-be.