Cardiotocography (CTG) is a procedure of graphically (graphy) recording fetal heart activity (cardio) and uterine contraction (toco)—both recorded in the same time scale simultaneously and continuously through uterine quiescence and contraction.
Though originally designed to monitor the fetus during labor so as to see how it performed on the face of the circulatory stress brought about by uterine contraction (see later), the scope of the method has now been widely enlarged to include the antenatal period as well where uterine contraction is not a factor except when it is artificially generated just for the test as in contraction stress test. (Caldeyro-Barcia and Alvarez, 1952; Hon EH, 1959; Cunningham et al, 2001).
It may be interesting to note that over the years CTG has become synonymous with the term ‘fetal monitoring’ and the CTG machine has come to be referred as the ‘Fetal Monitor’, and this is no wonder because 85% of births in USA get monitored by CTG (National Vital Statistics Report, USA, 2003).
FURTHER READING
- Caldeyro-Barcia, R Alvarez HJ. Obstet Gynaec Brit Emp 1952; 59: 646.
- Hon EH. Obstet Gynec 1959; 14: 154.
- National Vital Statistics Report, USA, 2003
- William's Obstetrics: 23rd Edition, Edited by Cunningham FG, Leveno KJ, Bloom SL, et al. Intrapartum Assessment, Mc Graw Hill, New York, 2010; 410-43.