The third trimester is a time that can be a filled with mixed emotions. You could be filled with excitement about the baby’s arrival and then be anxious about the baby’s health as well. What if something goes wrong at the last minute? Will everything go as planned? The cardiotocography is a technique that may help in alleviating some of your fears.
A cardiotocography is a technique that is used to monitor the heartbeat of the foetus along with keeping a check on uterine contractions. This can be deciphered from the name itself – cardio (heart) toco (uterine contractions) and graph (recording). A CTG Test during pregnancy is usually performed during the third trimester as well as during labour. The correct utilization of this test can help prevent the baby from dying due to a shortage of oxygen.
A CTG isn’t mandatory and low-risk pregnancies don’t require this. However, there are medical situations where the baby may be at risk such as:
CTG employs sound waves to help detect and monitor your baby’s heartbeat. Soundwaves in the form of ultrasound are used for a variety of medical purposes such as locating solid gallstones or blood clots. When ultrasound is targeted in a direction, it moves freely through fluids and soft tissue. However, it bounces back when it hits any solid objects and this shows up on the recording device. With this, doctors are able to identify what is inside the body without opening it up. Additionally, it can differentiate between densities (meaning it can tell the difference between bones, muscles and other parts of the body). CTG employs Doppler, a type of ultrasound that helps in studying moving objects. This becomes relevant in detecting the heartbeat of the baby.
Baby’s have a higher than average heart rate of 110-160 heartbeats every minute. Anything higher or lower than that may be indicative of a problem in your baby’s health. The CTG helps detect anomalies that may occur during contractions. The heartbeat during this time has a set pattern and specific changes may be indicative of a problem. If your doctor is convinced that the issue may jeopardize the pregnancy, they would start an emergency caesarean section or assisted delivery.
CTG has two main advantages that have made it popular, namely its non-ionizing properties and its non-invasive nature. Unlike X rays, ultrasound does not employ any ionizing radiation to take a look inside the body. This means that you and your child will have no risk of genetic damage. Non-invasive means that the procedure does not introduce instruments inside the body. For example, a Caesarean is highly invasive.
However, CTG does have a few drawbacks such as:
During CTG monitoring in pregnancy, the heart rate of the baby is constantly checked for any anomalies. The machine is equipped with a printer which allows you to have a look at the heart rate yourself. Below is a table which shows the range of what the registered values indicate.
Reading | Heart Beat per minute |
Safe | 110-160 |
Warning | 100-109 or 161-180 |
Threatening | Lower than 100 or more than 180 |
However, an immediate action such as Caesarean or assisted delivery based on these readings isn’t always recommended. Your doctor would usually follow up with a biophysical profile of the foetus to be certain.
Please note that the readings are not precise so do not be alarmed if you find anomaly the first time. There could be a number of reasons such as your baby falling asleep during the test. In such instances, either the baby is woken up using a stimulator or the test is performed after a while. However, there may be instances when it can alert the doctor of a failing pregnancy. In such instances, an emergency procedure can be performed and save the life of your child.