Procedures: Stress/Non-stress Tests

1. Non-Stress Test (NST) . The non-stress test has been a popular method of foetal surveillance for postterm pregnancies, however there is evidence to suggest that it is not an effective method of foetal surveillance.
   
2. Contraction Stress Test (CST) . Both nipple stimulation and intravenous oxytocin have been used as mechanisms for inducing contractions . The test results appear in some populations to correlate with outcome and some obstetricians prefer this test method of foetal surveillance. The disadvantages are that it takes time to administer and, in the case of oxytocin challenge test, requires an intravenous infusion.

In a high-risk pregnancy, electronic foetal heart monitoring is sometimes used as part of a nonstress test, in which the foetus' heart rate is monitored as the foetus lies still and moves. If the heart rate doesn't increase with movement, a contraction stress test may be performed. The foetus' heart rate is then monitored during the induced contractions to determine whether the foetus will be able to survive labour.

The information in this page is presented in summarised form and has been taken from the following source(s):
1. Hygeia Foundation : http://hygeia.org/