Cardiotocography (CTG)

Cardiotocography (CTG or non-stress test) is a diagnostic method used to monitor uterine contractions and cardiac output. It is most commonly used in the third trimester of pregnancy and it is recommended that after the 36th week of pregnancy, CTG be performed once a week or more frequently (if necessary). Recording takes about 20 minutes, and if the fetus is inactive or asleep, the recording may take longer than 20 minutes.

INDICATIONS / WHY IS IT WORKING?

• CTG is used in the assessment of fetal status before birth. The purpose of the test is to provide information on the fetal oxygen supply based on monitoring of cardiac output (heart rate) and fetal movement.
• A CTG may indicate (suggest) further testing (if necessary), more frequent and more detailed monitoring of pregnancy, or preterm delivery. The fetal heart rate is faster while it is active and in advanced pregnancy.
Your doctor may recommend a CTG if:
• as part of routine pregnancy monitoring.
• it is a multiple pregnancy accompanied by certain complications or if you have had complications in a previous pregnancy.
• you have an associated disease (diabetes, heart disease or high blood pressure).
• it is a matter of post-term pregnancy (pregnancy not completed at the scheduled time).
• there is a registered problem with fetal growth, you have insufficient water (amniotic fluid – oligohydramnion) or the fetus is less active than expected.
• Rh (rhesus) sensitization is suspected – a serious condition that can occur during the second, third, or subsequent pregnancy, when the mother’s Rh factor is negative and the fetal Rh factor is positive.

HOW DOES IT WORK?

• If the fetus is inactive or asleep, the physician will try to stimulate the fetus manually or by placing the device on a tummy making noise. Blood pressure is measured before the test and at intervals during the test. Recording is done in the supine position.
• The health care provider will place two harness straps on your abdomen. One conductor registers fetal heart activity and another conductor registers uterine contractions (by measuring the pressure of the abdominal wall during uterine contractions). Your doctor will ask you to record the movements of the fetus that you will feel. The CTG tape is interpreted by a gynecologist.

POTENTIAL RISKS

CTG is a non-invasive diagnostic method that cannot harm you or your baby.

PREPARATION

No special preparation is required for this test.