Wednesday, January 27, 2010

Fetal monitoring (CTG) made easy for the pregnant woman.........

A few basics about fetal monitoring, cardiotocograph (CTG).... what every woman needs to know about CTG; you only need to be monitored if you have a problem, there needs to be a medical reason for you to be monitored. Normal healthy low risk women do not need continous monitoring.

What is monitoring...well it is listening to the babys heart rate, that is having a CTG attached, this entails a toco to measure uterine contractions and a transducer to pick up the fetal heart beat. No admission CTG needs to be conducted unless there is a medical reason for doing so. You can have intermittent monitoring, where the midwife will listen with a Doppler and or pinnard, however the guidelines do say if you use a pinnard to use a Doppler as well so that the woman can also hear the baby's heart rate... it is reassuring for her.
What are some of the reasons to be monitored: breech presentation, antepartum bleeding, diabetes, prolonged rupture of membranes, pregnancy greater than 42 weeks, big or small baby, polyhydramnios (too much liquor/water) - oligohydramnios,(not enough liquor/water) multiple pregnancy, previous cesarean, pre-eclampsia, reduced fetal movements,changes in labour, or some medical condition in labour....

Before the CTG is commenced it is important for the midwife to take your pulse rate to compare it to the babys baseline to ensure they are not the same. Also your blood pressure needs to be recorded...

What the midwives are looking and listening for is that the baby's heart rate is between 110 - 160bpm and that the heart rate does not go below 110bpm... if it goes below 110bpm it is called a deceleration and we do not like to see this happen, it is not considered normal.
As the baby moves in utero the baby's heart rate will go up, due to his/her movements and it shows normal oxygen levels this is considered normal, this is called an acceleration.

The other consideration of a CTG is the variability, this is the most important factor, in simple terms variability is the saw tooth looking part of the trace if it is between 5-25bpm the baby is well oxygenated and you don't have anything to worry about. However baby's can sleep for 20-90mins whilst being monitored and the variability will be reduced that is less than 5bpm, so the trace will not look like a saw tooth... it will be flatter, if this lasts longer than 90mins then it needs to be investigated further... flat lines on a CTG are never good... and needs immediate intervention especially if there are decelerations as well.

Lets revise some facts: normal baseline 110-160bpm
The time to be concerned is when you have reduced variability, decelerations, and long decelerations....
accelerations are usually good... when you are in labour you do not need to see accelerations but should have good variability.

Continous fetal monitoring is not required for 'low risk women' however it is important to assess how well the baby is doing through labour. This can be done by intermittent monitoring.....pinnard and or Doppler every 15-30 mins once you are in established labour and every 5 mins in second stage of labour.....

Point to remember if you are ever concerned about the CTG speak to your midwife and ask her to explain what is happening..... always ask the question.

RANZCOG guidelines for fetal surveillance

The normal CTG has the following features:
• Baseline rate 110-160.
• Baseline variability of 5-25 bpm.
• Accelerations 15bpm for 15 seconds.
• No decelerations

The following features are unlikely to be associated with significant
fetal compromise when occurring in isolation:(RANZCOG)
• Baseline rate 100-109.
• Absence of accelerations.
• Early decelerations.
• Variable decelerations without complicating features.

The following features may be associated with significant fetal compromise
and require further action (RANZCOG)
• Fetal tachycardia. (fast heart rate over 160 bpm)
• Reduced baseline variability.
• Complicated variable decelerations.
• Late decelerations.(after the contraction)
• Prolonged decelerations.(greater than 3-5 mins)

The following features are very likely to be associated with significant fetal
compromise and require immediate management, which may include
urgent delivery (RANZCOG)

• Prolonged bradycardia (<100 bpm for >5 minutes)(RANZCOG)
• Absent baseline variability.(flat line)
• Sinusoidal pattern.(wave like pattern)
• Complicated variable decelerations with reduced


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