What Is a Contraction Stress Test? A contraction stress test measures the fetal heart rate after the uterus is stimulated to contract. This is done to make sure that during labor the fetus can handle contractions and get the oxygen needed from the placenta. Why Are Contraction Stress Tests Done? This test may be recommended when a nonstress test or biophysical profile (BPP, an ultrasound done with a nonstress test) indicates a problem. It can determine whether the baby's heart rate remains stable during contractions. Should I Have a Contraction Stress Test? Your doctor may schedule a contraction stress test if concerned about how your baby will respond to contractions or to determine the fetal heart rate response to stimulation. However, the test can induce labor. What Happens During a Contraction Stress Test? In this test, the uterus is stimulated with pitocin, a synthetic form of oxytocin (a hormone secreted during childbirth). This is done with injections of pitocin or by squeezing the mother's nipples (causing oxytocin to be secreted). The pitocin brings on mild contractions, letting doctors see the effect of contractions while monitoring the baby's heart rate. When Are Contraction Stress Tests Done? A contraction stress test can be done at 34 weeks or later. When Are the Results Available? Results of a contraction stress test are ready immediately. Back to Articles Related Articles Prenatal Tests: First Trimester Find out what tests may be offered to you during the first trimester of pregnancy. Read More Prenatal Tests: Second Trimester Find out what tests may be offered to you during weeks 13 through 26 of pregnancy. Read More Prenatal Tests: Third Trimester Find out what tests may be offered to you during weeks 27 through 40 of pregnancy. Read More Prenatal Tests: FAQs Every parent-to-be hopes for a healthy baby, but it can be hard not to worry. Find out what tests can keep you informed of your health — and your baby's — throughout pregnancy. Read More Prenatal Test: Nonstress Test This test checks to see if the baby responds normally to stimulation and is getting enough oxygen. It's done to check on the health of the fetus in a high-risk pregnancy or when the due date has passed. Read More A Week-by-Week Pregnancy Calendar Our week-by-week illustrated pregnancy calendar is a detailed guide to all the changes taking place in your baby - and in you! Read More Medical Care During Pregnancy The sooner in pregnancy good care begins, the better for the health of both moms and their babies. Here's what to expect. Read More Inducing Labor Find out why doctors may induce labor if you're past your due date, how it may be done, and how it may affect you and your baby. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.