While you are pregnant, your health care provider may do tests to check your baby's health. The tests may be done at any time while you are pregnant.

Prenatal care - monitoring; Pregnancy care - monitoring; Non-stress test - monitoring; NST- monitoring; Contraction stress test - monitoring; CST- monitoring; Biophysical profile - monitoring; BPP - monitoring

Tests may be needed for women who:

• Have a high-risk pregnancy
• Have a health condition, such as diabetes
• Have had complications in a prior pregnancy
• Have a pregnancy that lasts longer than 40 weeks (overdue)

The tests may be done more than once so your provider can track the progress of your baby over time. They will help your provider find problems or things that are not normal (abnormal). Talk to your provider about your tests and the results.

A healthy baby's heart rate will rise from time to time. During the non-stress test (NST), your provider will watch to see if your baby's heart rate goes faster while resting or moving. You will receive no medicines for this test.

If your baby's heart rate does not go up on its own, you may be asked to rub your hand over your belly. This may wake up a sleepy baby. A device may also be used to send a noise into your belly. It will not cause any pain.

You will be hooked up to a fetal monitor, which is a heart monitor for your baby. If your baby's heart rate goes up from time to time, the test results will most likely be normal. NST results that are reactive mean that your baby's heart rate went up normally.

Non-reactive results mean that your baby's heart rate did not go up enough. If the heart rate does not go up enough, you may need more tests.

Another term you might hear for this test result is a categorization of 1, 2, or 3.

• Category 1 means the result is normal.
• Category 2 means further observation or testing is necessary.
• Category 3 typically means your provider will recommend delivery right away.

If the NST results are not normal, you may need a CST. This test will help the provider know how well the baby will do during labor.

Labor is stressful for a baby. Every contraction means the baby gets less blood and oxygen for a short while. For most babies this is not a problem. But some babies have a hard time. A CST shows how the baby's heart rate reacts to the stress of contractions.

A fetal monitor will be used. You will be given oxytocin (Pitocin), a hormone that makes the uterus contract. The contractions will be like the ones you will have during labor, only milder. If your baby's heart rate slows down rather than speeds up after a contraction, your baby may have problems during labor.

In some clinics, while your baby is being monitored, you may be advised to provide mild nipple stimulation. This stimulation often leads to your body releasing small amounts of oxytocin which will make your uterus contract. Your baby's heart rate is monitored during the resulting contractions.

Most women feel mild discomfort during this test, but not pain.

If the results are abnormal, your provider may admit you to the hospital to deliver your baby early.

A BPP is an NST with an ultrasound. If the NST results are not reactive, a BPP may be done.

The BPP looks at your baby's movement, body tone, breathing, and the results of the NST. The BPP also looks at the amount of amniotic fluid surrounding your baby, which is the liquid that surrounds your baby in the uterus.

The BPP test results can be normal, abnormal, or unclear. If the results are unclear, you may need to repeat the test. Abnormal or unclear results may mean that your baby needs to be delivered early.

A MBPP is also a NST with an ultrasound. The ultrasound looks only at how much amniotic fluid there is surrounding your baby. The MBPP test takes less time than a BPP. Your provider may feel that the MBPP test will be enough to check your baby's health, without doing a full BPP.

In a healthy pregnancy, these tests may not be done. But you may need some of these tests if:

• You have medical problems
• You have the potential for pregnancy problems (high risk pregnancy)
• You have gone a week or more past your due date

Talk to your provider about the tests and what the results mean for you and your baby.

Greenberg MB, Druzin ML. Antepartum fetal evaluation. In: Landon MB, Galan HL, Jauniaux ERM , et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 27.

Kaimal AJ. Assessment of fetal health. In: Lockwood CJ, Copel JA, Dugoff L, et al, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 32.