What is negative and positive contraction stress test?
Negative CST - If there are no late decelerations, it is called as negative CST. Negative CST is good. If late decelerations are absent, then, fetal deaths in following week is 1/1000. IT SIGNIFIES THAT INTERVILLOUS BLOOD FLOW IS OK.
Positive CST – if there are repetitive late decelerations, it is called as positive CST. Positive CST is bad. There should be gradual increase or decrease in FHR and delayed relative to uterine contractions.