STAN™ is a system for fetal surveillance that displays the FHR, the uterine activity and information resulting from the computerized analysis of the ST interval of the fetal ECG.
This real-time analysis is referred to as ‘ST Analysis’ and is based on ECG changes determined by the myocardial adaptation to oxygen deficiency.
The STAN system is based on a combination of FHR interpretation and ST Analysis, where both parts are of equal importance. The FHR must be correctly interpreted and evaluated in relation to the ST Analysis in order to determine the recommended clinical actions.
ST Analysis is indicated as an adjunct to FHR monitoring to determine whether obstetrical intervention is warranted when there is increased risk of developing metabolic acidosis. The intended use is in patients with planned vaginal delivery, a term pregnancy of 36 or more completed gestational weeks, singleton fetus, vertex presentation and ruptured amniotic membranes. Use of the STAN S31 monitor fetal ECG analysis function is contraindicated in situations with Non-reassuring, Grade 2 FHR classification (as defined in the STAN Training Materials); when use of a fetal scalp electrode is contraindicated such as patients with HIV, infectious hepatitis, active herpes simplex virus, and known or suspected fetal coagulation disorder; in patients with fetal bleeding disorders; when monitoring is initiated in the second stage of labor; in patients experiencing precipitous labor; in patients receiving TENS for analgesia during labor; and in patients requiring immediate delivery.
For a complete list of the indications, contraindications, warnings and precautions, see here.
The Center for Devices and Radiological Health of the Food and Drug Administration (FDA) has reviewed and approved the pre-market approval application (PMA) for STAN S31 on November 1, 2005.

