Today we are going to talk about CTG (Cardiotocography) and how to interprate a CTG strap.

First of all, one of the transducer shall be put over the fundus of the uterus, while another at the place where the fetal heart beat is best heard. And then the FHR and Uterine Contraction will be recorded. These are few principles that one should know in order to interprete the CTG.

Baseline FHR- It is the mean of the peaks and depressions. Normal would be 110-150bpm (beats per minute)

Baseline variability - It is the oscillation of baseline FHR excluding acceleration and deceleration. Normal would be 10-25bpm

Acceleration – It is the increase of FHR for more at least 15seconds. Normal would be 2 in 20min

Deceleration – It is the decrease of FHR below the baseline by 15bpm or more. Normal would be none or early.

The deceleration pattern could be early, late and variable.

Early deceleration means the FHR begins to slow down at the beginning of UC. The lowest point of deceleration conincides with the peak of UC.

Late deceleration means the FHR begins to slow down after the onset of the contraction. The lowest point is thus after the UC and usually FHR would return to normal before the next contraction.

Variable deceleration means all other patterns of FHR slowing which not necessarily related to UC.

Lag time is the time taken for the FHR to reach the lowest point (nadir) from the peak of UC.

Sinusoidal pattern is the stable baseline FHR without any acceleration. This is usually associated with fetal anaemia, feto-maternal hemorrhage and fetal hypoxia.

That’s all for this time. Read this and try to find more articles online. Hopefully you wouldn’t be so blur when the teacher shows you the CTG in the future!