Over the course of your pregnancy, you will be undergoing several prenatal tests to check on your baby and ensure that he or she gets the best care. One such test, which is usually given during your third trimester, is the contraction stress test. Also known as an oxytocin challenge test, this prenatal examination is commonly required among pregnant women, although some may not need one.
With all the clinical tests expectant moms usually undergo throughout their pregnancy, it’s easy to feel overwhelmed—that is, if they’re not already. If you’re one of these moms, put yourself at ease by learning more about contraction stress test.
- It determines your baby’s reaction to labor.
A contraction stress test works by predicting how your baby will do once labor starts. During the test, your baby’s heart rate during contractions will be measured and recorded. Contractions may slow down the blood and oxygen flow to the placenta temporarily. But if the placenta is healthy, it will supply your baby with enough blood and oxygen to withstand contractions, so your baby should be okay. A contraction stress test determines whether or not your child will receive the oxygen that he or she needs once the contractions begin during labor.
- It triggers contractions.
For the test to work, invariably, it has to initiate contractions to get a reaction from your baby, which is why although a contractions stress test is usually safe, it may trigger early labor. Usually, this test is riskier for women who are at risk for uterine rupture, who are carrying multiple babies, have placenta previa, or have had a C-section previously. Upon consultation, your doctor should be able to help weigh the pros and cons of the test before recommending it.
- It serves as a follow-up test.
A contraction stress test may usually be required in high-risk pregnant women. Particularly, it may be suggested as a follow-up examination if a non-stress test or a biophysical profile yielded abnormal results.
- It takes about two hours.
During a contraction stress test, you will be asked to lie down while two belts are strapped around your abdomen. One is used to measure your baby’s heart rate and the other is a toco transducer rolled gently over the abdomen to measure the contractions. A machine then records the fetal heartbeat in response to uterine contraction and prints the recording on paper.
If you don’t get contractions on your own, your doctor may either administer a dose of oxytocin through an IV or suggest that you stimulate your nipples to allow the body to produce the hormone itself. The entire test usually takes around two hours, but you may be advised to stick around and wait for your contractions to stop or return to their pretest level.
- An abnormal result may mean early delivery.
Results of a contraction stress test can be accessed immediately. A normal result, also known as reactive, shows when the baby’s heart rate does not slow down as a response to contractions. This means that the baby is doing fine inside the womb. Otherwise, in an abnormal or nonreactive result, which occurs when the baby’s heart rate decreases when a contraction comes on, the baby may be under stress and may have to be delivered earlier than expected, either through labor induction or a possible C-section. Don’t worry; your options will be discussed with you by your doctor.
A contraction stress test may be recommended by your doctor if need be; otherwise, there are more non-invasive options that may be suggested to you. Either way, all of these tests can help guarantee your child’s safety and a smooth-sailing delivery.