E, 32, was eagerly awaiting the arrival of her first child. Her excitement was palpable as she had been trying to conceive for the past 4 years since she got married. As she entered the 36th week of her pregnancy, a mix of joy and anticipation filled her days. On the day of her routine antenatal check-up, she felt that her baby did not move as much as on the previous day. “Doc, my baby’s movement has a pattern that I can almost predict every day. But today, somehow, I feel his movements have reduced a lot,” she said anxiously. She was put on the CTG machine immediately. CTG recording revealed an abnormal tracing of the fetal heartbeat pattern, indicating signs of fetal distress. She was admitted to the hospital right away for further monitoring.
What is CTG?
CTG or Cardiotocograph is a non-invasive medical procedure in which a continuous electronic record of the fetal heart rate is obtained by an ultrasound transducer placed on the mother’s abdomen. It measures the response of fetal heart rate during different phases of the uterine contractions. Thus, it is very useful in assessing the well-being of the unborn baby and in identifying any potential issues that may require obstetrical intervention. It can be used during the antenatal period as well as when a patient is in labour.
How is CTG done?
Two transducers are strapped around the women’s abdomen. One transducer monitors the fetal heart rate while the other records the uterine contractions (Fig. 1).
Fig 1
The fetal heart rate is calculated from fetal heart motion determined by ultrasound, and uterine contractions are measured by a tocodynamometer. The data obtained from the transducers is printed out as graphs on a running piece of paper. (fig 2)
Fig 2
When should Antenatal CTG be done?
Antenatal CTG is commonly used in the third trimester of pregnancy to assess fetal wellbeing in high-risk pregnancies. These include:
Maternal conditions: Essential hypertension, pre-eclampsia, kidney disease, diabetes and thyroid disease
Pregnancy complications: Reduced fetal movement, vaginal bleeding
Fetal conditions: Intrauterine growth restriction (IUGR), fetal infection and multiple pregnancies
CTG can also be used in combination with other methods of fetal assessment such as ultrasound Doppler measurements of the placental, umbilical and fetal blood flow and amniotic fluid volume measurement.
Conclusion:
Antenatal CTG provides valuable data that can be used to make informed decisions regarding the management of labour and delivery. This information helps determine whether the fetus can tolerate the labour process well or if any medical interventions are needed. In managing high-risk pregnancies, such timely decisions are important for optimal outcomes.
While CTG is a valuable tool, it is important to note that its interpretation requires the expertise of trained healthcare professionals. Otherwise, it may cause much anxiety to the mothers and also many unnecessary instrumental deliveries and cesarean sections.
After admission to the hospital, E's CTG recording remained abnormal. An emergency caesarean section was done immediately. Thick meconium was found in the amniotic fluid indicating insufficient oxygenation to the fetus antenatally. A male fetus weighing 2.5 kg was delivered. He was slightly feeble at delivery but recovered well shortly after resuscitation.