What is a CTG

What is a CTG?

Monitoring of the baby's heart rate during labour can be done using a 'Continuous Cardiotocographic machine' (or CTG). This records the baby's heart rate continuously on a piece of paper. Caregivers often refer to the paper recording as a 'trace'. A CTG may also be referred to as fetal monitoring, continuous monitoring, and electronic fetal monitoring (or EFM).

The CTG was first developed in the 1970's and is now a widely used tool to monitor babies during labour in maternity hospitals throughout Australia (and in most modern delivery suites worldwide). A CTG may also be performed during the last half of the pregnancy (usually after 24 to 28 weeks) if there are health concerns for the mother or baby.

Reasons to monitor the baby's heart rate can include:

If there are health concerns for the mother during late pregnancy. This can include bleeding, high blood pressure, premature labour, diabetes, cholestasis, kidney or heart disease .
	If there are health concerns for the baby such as small for dates, an abnormality of the baby, or the pregnancy is very overdue.
	As a routine procedure during labour. Some delivery suites have a policy to perform a routine 20 minute recording of the baby's heart rate when the woman arrives in labour, even if there are no complications.
	If the waters break and the labour has not started. If the woman is waiting for her labour to start with ruptured membranes, the caregiver may perform a 20 minute trace to check her baby's well being. You can read more in waters breaking, no contractions.
	If the baby is showing signs of distress. This can be if the baby's heart rate is noticed to be lower, when the caregiver is listening intermittently (usually after a contraction during labour), or if the waters break and there is meconium staining of the amniotic fluid. This is discussed further in fetal distress.
	If the labour is being induced or augmented with an oxytocin drip or prostaglandins. These medications have the potential to overstimulate the uterus and distress the baby, therefore continuous monitoring of the baby's heart rate is usually advised when using these interventions. These are discussed in depth in Class 4, Induction and augmentation.
	If the woman is having an epidural for pain relief in labour. The baby's heart rate can lower in response to a fall in the woman's blood pressure, a possible side effect of an epidural. Caregivers usually like to have the monitor in place when an epidural is being used. You can read more on this in epidurals for pain relief.