Monitoring your baby before labor
Tests you may need before labor
While you are pregnant, your doctor may do tests to check your baby's health. The tests may be done at any time while you are pregnant. 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 the doctor can track the progress of the baby over time. They will help the doctor find problems or things that are not normal (abnormal). Talk to your doctor about your tests and the results.
Non-stress test (NST)
A healthy baby's heart rate will rise from time to time. During the NST, your doctor will watch to see if the baby's heart rate goes faster while resting or moving. You will receive no medicines for this test.
If the 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 the 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 the baby's heart rate went up normally.
Non-reactive results mean that the 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 doctor will recommend delivery right away.
Contraction stress test (CST)
If the NST results are not normal, you may need a contraction stress test (CST). This test will help the doctor 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 the baby's heart rate slows down rather than speeds up after a contraction, the baby may have problems during labor.
Most women feel mild discomfort during this test, but not pain.
If the results are abnormal, your doctor may admit you to the hospital to deliver the baby early.
Biophysical profile (BPP)
A biophysical profile (BPP) is a non-stress test (NST) with an ultrasound. If the NST results are not reactive, a BPP may be done.
The BPP looks at the baby's movement, body tone, breathing, and the results of the NST. The BPP also looks at amniotic fluid, which is the liquid that surrounds the 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. Results that are not normal may mean that the baby needs to be delivered early.
Modified biophysical profile (MBPP)
A modified biophysical profile (MBPP) is also a non-stress test (NST) with an ultrasound. This test looks only at how much amniotic fluid there is. The MBPP test takes less time than a BPP. Your doctor may feel that the MBPP test will be enough to check the 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 doctor about the tests and what the results mean for you and your baby.
Gerber SE. Estimation of fetal well-being. In: Martin RJ, Fanaroff AA, Walsh MC, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine. 9th ed. St. Louis, MO: Elsevier Mosby. 2010:chap 10.
Cynthia D. White, MD, Fellow American College of Obstetricians and Gynecologists, Group Health Cooperative, Bellevue, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.