What is a Stress Test During Pregnancy?

What is a Stress Test During Pregnancy?

What is a Stress Test? Types of Stress Tests

A stress test during pregnancy is a medical procedure to assess the baby’s well-being while in the womb. The test is performed to help detect any potential problems or complications with the baby before it is born. The stress test can be performed when you are in the third trimester of pregnancy, usually from 32 weeks onward.

The test is performed by monitoring the baby’s heart rate in response to various activities. This can involve the mother engaging in some physical activity such as walking or running on a treadmill, or by stimulating the baby with a sound or light. The baby’s oxygen levels are then monitored to judge its response and ability to handle the stress.

There are two types of stress tests used during pregnancy: the non-stress test (NST) and the contraction stress test (CST).

A non-stress test (NST) is a non-invasive prenatal monitoring technique performed during pregnancy to assess the fetal heart rate and its response to fetal movement.

A contraction stress test (CST) is a prenatal diagnostic procedure performed during pregnancy to evaluate how the fetus responds to uterine contractions. This test assesses the fetal heart rate in response to induced contractions, helping to determine if the baby is receiving adequate oxygen supply.

The non-stress test is typically done in the late second or third trimester, while the contraction stress test can be done as early as the 28th week of pregnancy.

Is a Stress Test during Pregnancy Necessary?

The test is usually recommended if you are at higher risk for complications due to age, medical history, or other factors.

The stress test can be beneficial to take because it can identify any problems early on in the pregnancy. For example, if your heart rate is too high during the test, it may indicate an increased risk for problems such as pre-eclampsia or gestational diabetes. This can help the doctor or midwife to take steps to help manage the health of yours and the baby.

Additionally, a stress test can provide you a peace of mind. Knowing that the baby is doing well and that the pregnancy is progressing normally can be a huge relief for you who can be anxious about the health of your baby.


doctor is checking pregnant woman with stethoscope


What is the Purpose of Stress Tests during Pregnancy?

A contraction test and a non-stress test are two of the most common tests performed during pregnancy. Both tests are used to monitor your health and of your baby’s.

The aim of the contraction stress test is to monitor the baby’s heart rate and see how it responds to your uterus contractions. During the test, the mother will be asked to lie on her back and the doctor will monitor the baby’s heart rate with a special device. The doctor will then induce contractions and monitor the baby’s heart rate to see how it reacts. If the baby’s heart rate drops below a certain level or does not increase during the contractions, this could indicate a potential complication with the pregnancy.

The purpose of a non-stress test is to measure how the baby’s heart rate responds to its own movement. A normal fetal heart rate is between 110-160 beats per minute. During the test, the baby’s heart rate will increase when it moves and this is called acceleration. If the baby’s heart rate does not increase and remains at a constant rate, then this is known as a non-reactive test and can indicate a problem.


How are Stress Tests during Pregnancy Done?

A non-stress test is performed by a doctor or nurse in a clinic or hospital. The test begins with you lying down on your back on an exam table. A belt is placed around your abdomen and is connected to a monitoring machine. This machine monitors the baby's heart rate and records the information on a graph. You are then asked to remain still and press a button every time you feel your baby move.

The NST typically lasts 20-40 minutes. During this time, the monitoring machine will alert the doctor if the baby's heart rate increases or decreases in response to its own movements. This indicates that the baby is healthy and responding normally.

If the baby's heart rate does not increase or decrease in response to its own movements, then it is an indication that the baby may be in distress. This is known as a non-reactive or “silent” NST. In this case, the doctor may order additional tests to determine the cause of the problem.

If the NST is reactive and the baby's heart rate is normal, then you can usually be reassured that your baby is healthy. However, it is important to keep in mind that the NST is not a diagnostic test and should not be used as the sole indicator of fetal health. It can be accompanied by other tests and medical advice to make an informed decision about the baby's wellbeing.

Speaking about contraction stress test, the doctor will start by performing a fetal monitoring test to check the baby’s heart rate and your contractions. A doctor or nurse will then use a device called a tocodynamometer, which is a belt wrapped around your abdomen and connected to a monitor that records the baby’s heart rate and the strength of the contractions.

Your doctor will then give you medicine to induce contractions. This medicine, called oxytocin, is administered through an intravenous (IV) line. You will be asked to relax and stay still during the contractions, and the nurse or doctor will monitor your baby’s heart rate and the strength of the contractions.

The test will last around 20 minutes, during which time the baby’s heart rate should remain steady and increase with each contraction. If the baby’s heart rate drops significantly or does not increase with the contractions, it could be a sign of distress, and the doctor may recommend further testing or interventions.

After the test is complete, your doctor or nurse will discuss the results with you. If the results are normal, your doctor may recommend follow-up tests or monitoring to ensure the baby is healthy. If the results are not normal, your doctor may recommend further testing or interventions.

Both non-stress tests and contraction stress tests are important tests for monitoring the health of a fetus during pregnancy. They are both safe and non-invasive procedures that can help detect any problems that could affect the baby’s health. By monitoring the baby’s heart rate and movement, doctors can identify if the child receives enough oxygen and nutrients and develops normally. If anything appears to be wrong, the doctor can take appropriate action to ensure the baby’s health.


Ultrasound consultation for pregnant woman

What are the Results of a Stress Test during Pregnancy?

The results of a non-stress test and contraction stress test during pregnancy can be quite useful in determining the health of the fetus and the progress of the pregnancy. An NST will usually provide a baseline fetal heart rate and will also show any changes in the rate when the baby moves. If the results of an NST are abnormal, it may indicate that the baby lacks oxygen or it may be another issue with the fetus.

The CST results will provide information about the strength of the contractions and any changes in the baby’s heart rate during the contractions and whether there is adequate oxygen being delivered to the baby during labor.

The results of NSTs and CSTs are important for your and your baby’s health. If the results of either test show abnormalities, further tests may be recommended to ensure that the baby is healthy and that labor is progressing normally.

Maybe you are asking yourself whether Stress Can Cause Bleeding During Pregnancy, is there any connection between stress and bleeding, and why bleeding can occur. We will explain everything about the topic in our article.

Moreover, in this current article the process and importance of conducting stress tests during pregnancy are emphasized, revealing how they can accurately diagnose potential complications. This understanding serves as a crucial link to the another article about Maternal Stress During Pregnancy which extensively discusses the causes, signs, effects on both you and the developing fetus. The information from both articles underscores the importance of stress management, emphasizing that understanding your stress response can guide effective strategies to ensure the healthy well-being of you and your baby.


In conclusion, stress tests during pregnancy, such as non-stress and contraction stress tests, are crucial tools for monitoring the health of a developing fetus. These tests can help detect potential complications and provide valuable information about the baby's well-being. Performed during the second and third trimesters of pregnancy, these tests are particularly beneficial if you are with higher risks for complications due to age, medical history, or other factors.

Both NST and CST are non-invasive and safe procedures that can identify early signs of issues such as inadequate oxygen supply or abnormal heart rate responses. These tests not only play a critical role in prenatal care, but they also calm you down by reassuring you of your baby's health state. However, it is necessary to mention that stress tests should not be used as the sole indicators of fetal health. They should be complemented with other tests and medical advice to make well-informed decisions about the baby's well-being.

Results from stress tests during pregnancy are invaluable in determining the health of the fetus and the progress of the pregnancy. Abnormal results may prompt further testing or interventions to ensure the baby's health and the proper progression of labor. Ultimately, these tests play a vital role in ensuring that potential complications are detected and addressed in a timely manner, contributing to healthier pregnancies and better outcomes for both you and the baby.



Griffin R. M. Contraction Stress Test (CST). Grow by WebMD, 19 March 2021

Prenatal Non-stress Test - StatPearls - NCBI Bookshelf (nih.gov)   

Umana OD, Siccardi MA. Prenatal Non-stress Test. In: StatPearls [Internet]. National Library of Medicine (NIH). 19 Feb 2023

Cleveland Clinic. Health library. Diagnostics & Testing. Contraction Stress Test, 26 April 2022

Miles K. Contraction stress test. BabyCenter. 19 July 2020

Miles K. Non-stress Test. BabyCenter. 9 August 2021

Brazier Y. What you need to know about the stress test. MedicalNewsToday, 25 April 2023.

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