WHY NST IS DONE

What is NST?

NST, or Non-Stress Test, is a prenatal test used to assess the well-being of a fetus. It is a simple and non-invasive procedure that measures the baby's heart rate and its response to movement. NSTs are typically performed in the third trimester of pregnancy (after 28 weeks) to check for signs of fetal distress or poor placental function. Unlike the other numerous NST tests performed to assess fetal behavior and health, NST is unique. From detecting fetal heart rate variability to testing fetal oxygen reserves, NST is a comprehensive examination that can provide valuable details about the status of the baby.

Why is NST Done?

NSTs are done to:

• Monitor fetal well-being: NSTs can help to identify fetuses that are at risk for distress or death. This is done by measuring the baby’s heart rate and its response to movement. A normal NST result indicates that the baby is healthy and getting enough oxygen.
• Diagnose fetal distress: NSTs can help to diagnose fetal distress, which is a condition in which the baby is not getting enough oxygen. Signs of fetal distress include a decreased heart rate, an increased heart rate, or a lack of heart rate variability.
• Assess placental function: NSTs can help to assess placental function, which is the ability of the placenta to provide oxygen and nutrients to the baby. A decreased heart rate or an increased heart rate can be a sign of placental insufficiency.

NST Procedure

NSTs are typically performed in a doctor's office or hospital. The procedure is simple and non-invasive. Here's a step-by-step explanation of the NST procedure:

• Preparation: The pregnant woman will be asked to lie on her back on an examination table. The doctor or nurse will place two belts, one around her abdomen and one around her uterus. The belts contain transducers that will measure the baby’s heart rate and uterine contractions.
• Test duration: The NST typically lasts for 20 to 30 minutes. During this time, the doctor or nurse will monitor the baby’s heart rate and uterine contractions. They will also ask the pregnant woman to press a button each time she feels her baby move.
• Evaluation: After the test is complete, the doctor or nurse will evaluate the results. A normal NST result indicates that the baby is healthy and getting enough oxygen. An abnormal NST result may be a sign of fetal distress or placental insufficiency. If the NST result is abnormal, the doctor may order additional tests to confirm the diagnosis.

NST Interpretation

NST results are interpreted based on the baby's heart rate and its response to movement. A normal NST result includes:

• A baseline heart rate between 110 and 160 beats per minute (bpm)
• At least two accelerations of at least 15 bpm lasting at least 15 seconds
• No decelerations (slowing of the heart rate) lasting more than 15 seconds

An abnormal NST result may include:

• A baseline heart rate below 110 bpm or above 160 bpm
• Less than two accelerations of at least 15 bpm lasting at least 15 seconds
• Decelerations (slowing of the heart rate) lasting more than 15 seconds

NST Risks

NSTs are generally considered to be safe for both the mother and the baby. However, there are a few potential risks associated with the procedure, including:

• Discomfort: The belts used to measure the baby’s heart rate and uterine contractions may cause some discomfort.
• False positive results: NSTs can sometimes produce false positive results, which may lead to unnecessary additional testing or interventions.
• False negative results: NSTs can also produce false negative results, which means that a problem with the baby may be missed. This is why it is important to have regular prenatal visits and to see your doctor or midwife if you have any concerns about your baby’s health.

Conclusion

NSTs are a valuable tool for assessing fetal well-being. They are simple, non-invasive, and can help to identify fetuses that are at risk for distress or death. NSTs can also be used to diagnose fetal distress and to assess placental function. NSTs are typically performed in the third trimester of pregnancy, although they can be done earlier if there are concerns about the baby's health.

FAQs

Q: What is the purpose of an NST?
A: NSTs are used to assess fetal well-being, diagnose fetal distress, and assess placental function.

Q: When is an NST typically performed?
A: NSTs are typically performed in the third trimester of pregnancy, although they can be done earlier if there are concerns about the baby's health.

Q: What are the risks associated with an NST?
A: NSTs are generally considered to be safe, but there are a few potential risks, including discomfort, false positive results, and false negative results.

Q: How long does an NST typically last?
A: NSTs typically last for 20 to 30 minutes.

Q: What are the signs of a normal NST result?
A: A normal NST result includes a baseline heart rate between 110 and 160 beats per minute (bpm), at least two accelerations of at least 15 bpm lasting at least 15 seconds, and no decelerations (slowing of the heart rate) lasting more than 15 seconds.