Understanding fetal monitoring in labour

Measuring an unborn baby’s heart rate is a good way for a midwife to check the baby’s health during pregnancy and labour.  A normal heart rate can reassure the mother’s maternity team that it is safe to continue labour if no other problems are present.  An abnormal heart rate may be a sign that the baby is in difficulty and needs help to be delivered safely.

How is an unborn baby’s heart rate monitored during labour?

There are various different methods of monitoring the fetal heart rate. Intermittent auscultation (IA) can be carried out by:

• Pinard stethoscope - a type of ear trumpet which the midwife places on the mother’s abdomen through which she can hear and count the baby’s heartbeat; or
• Doppler (or Sonicaid) - a small, portable machine which uses ultrasound through a transmitter on the mother’s abdomen to pick up the baby’s heartbeat.

Electronic fetal monitoring (EFM) or cardiotocography (CTG) involves strapping transducer sensors to the mother’s abdomen. These pick up signals from the baby’s heartbeat and maternal contractions and show them on a monitor.  The CTG monitor produces a print-out of a continuous graph (often called a ‘trace’) which shows the baby’s heart rate in response to the maternal contractions.  

If electronic fetal monitoring indicates that there may be a problem with the baby’s heart rate then a fetal scalp electrode (FSE) may be used to obtain a more direct and reliable reading of the baby’s heartbeat. FSE is an internal method of fetal heart rate monitoring which involves passing a small electrode through the mother’s vagina and open cervix and attaching it to the baby’s scalp. The FSE picks up the baby’s heartbeat and sends it to a monitor which produces a print-out of the fetal heart rate. The results of the FSE monitoring will determine if labour can safely carry on or if an assisted birth (with forceps or ventouse suction) or a caesarean section are required urgently. 

Which method of monitoring will be used?

In uncomplicated pregnancies, where labour is progressing well and no problems are identified, often the only monitoring that will be done will be intermittent monitoring with a Pinard stethoscope or Doppler. Typically a midwife will listen to the baby’s heart during and after some contractions to see how well the baby is coping.

Continuous electronic fetal monitoring with CTG is usually only recommended if:

• the mother has an epidural;
• the mother has an oxytocin (Syntocinon) drip to help speed up labour;
• there is a lack of progress in labour;
• there is a significant amount of meconium (baby poo) when the waters break;
• there are concerns about the baby’s heartbeat;
• the mother has high blood pressure, a temperature or a high pulse rate or infection;
• maternal fresh vaginal bleeding develops in labour;
• maternal pain differs from the pain normally associated with contractions;
• maternal contractions last longer than 60 seconds or more than 5 contractions occur in 10 minutes;
• the mother is expecting more than one baby (twins or triplets).

Reviewing and interpreting the CTG

Healthcare professionals are trained to look at the following four particular features on a CTG trace of the fetal heart rate to work out whether or not it shows that the baby is doing well:

1. Baseline rate;
2. Baseline variability;
3. Presence or absence of decelerations;
4. Presence of accelerations.

Depending on what these features show, a trace will be categorised as ‘normal’, ‘suspicious’ or ‘pathological’, and action will be taken to speed up labour/delivery depending on the category.

CTG monitoring alone is not a 100% reliable method of checking how a baby is coping with labour.  Errors in its use and interpretation are all too common and traces can sometimes be classified as ‘normal’ or ‘suspicious’ when, in fact, the baby is in distress and needs urgent delivery.  Even in skilled hands, not all patterns associated with distress of an unborn baby are currently known.  Therefore, whilst CTG monitoring is a very useful indication of how the baby is coping, it must be considered together with other factors, such as known and anticipated risks, the history of the pregnancy, maternal health and concerns, to ensure a safe delivery for mother and baby.

Fetal heart monitoring errors are a common factor in birth injury  

In recent years, the importance of accurate fetal monitoring during labour  has repeatedly been highlighted in national reports, by organisations including The Royal College of Obstetricians and Gynaecologists (RCOG), HSIB, MNSI and the NHS’s defence organisation, NHS Resolution.

Early data from NHS Resolution’s Early Notification Scheme found that poor fetal monitoring was a leading contributory factor in 70% (i.e. more than two thirds) of cases involving injury to the mother or baby. In 63% of cases there were two or more fetal heart monitoring errors, including a delay in acting on an abnormal fetal heart rate and/or a delay in escalation and/or an incorrect classification. This led NHS Resolution to conclude that problems with fetal monitoring were still the major contributing factor in poor outcomes at birth, despite widespread initiatives aimed at improving the situation.

An analysis by MNSI into its predecessor HSIB’s maternity safety investigations found that poor reliability of monitoring by intermittent auscultation (IA) is a common factor in birth injuries to babies born in midwife-led units. MNSI also pointed to research which has found that failures in timing, recording, interpretation of IA and failing to take action in response to fetal heart rate abnormalities found during IA monitoring commonly contribute to poor outcomes suffered by babies. HSIB’s own reviews have also identified issues with CTG monitoring and CTG equipment. 

Boyes Turner’s nationally acclaimed birth injury solicitors have been helping families of brain injured babies recover top level compensation awards for over 30 years. We are known for our outstanding expertise and success in complex cerebral palsy and birth-related injury claims including those involving errors in the use of fetal monitoring, its interpretation and delayed response to signs of fetal distress.

If your child has cerebral palsy or neurological disability as a result of medical negligence, or you have been contacted by HSSIB/MNSI or NHS Resolution, you can talk to a solicitor, free and confidentially, for advice about how to respond or make a claim by contacting us.