June 27, 2023

Impacted fetal head – what you need to know

The NHS Litigation arm (NHS Resolution) has reported that one of the largest areas of litigation relating of the mis-management of birth is associated with impacted fetal head. The exact reason for this is unknown but it is likely associated with a lack of research, guidelines and training available to obstetricians and midwives on how to manage this obstetric emergency.

What is impacted fetal head (IFH)?

Impacted fetal head is when the baby’s head is positioned very low in the maternal pelvis and is fixed, so cannot be moved to enable delivery of the fetal head during a lower section caesarean section.

What causes impacted fetal head?

Difficult delivery of the fetal head during a caesarean section may arise when the baby’s head becomes impacted in the maternal pelvis during the course of labour. Strong uterine contractions can lodge the baby’s head firmly in the pelvis, making extraction of the head during a caesarean delivery extremely difficult.

Impacted fetal head appears to be more common when a decision is made to deliver by caesarean section at a later stage of labour. Therefore extraction of the head may be more difficult in situations where there has been a failed attempt to deliver the baby by instrumental delivery or a failed induction of labour.

What are the complications of impacted fetal head?

A difficult extraction of the head during a caesarean section can lead to complications for both the mother and the baby. This may include a mother experiencing severe bleeding or injury to the surrounding tissues.

When impacted fetal head occurs there is a significant risk to the baby that they will become deprived of oxygen due to compression on the umbilical cord and oxygen supply with descent of the baby’s head and body. If the baby is deprived of oxygen for a significant period of time, then this may result in hypoxic injury to their brain and permanent damage, resulting in cerebral palsy.

How should impacted fetal head be managed?

There is currently no national guidance in terms of clear protocols for the management of IAH. The lack of research and evidence means that there is no formal (Green Top Guidance) from the Royal College of Obstetricians and Gynaecologists (RCOG). Other Guidance has been provided by the PROMPT Foundation, who created an algorithm on management of IFH.

A paper has been published in June 2023 on Management of Impacted Fetal Head at Caesarean Birth – this will now create a new national Guide, but it is not sufficient of data to enable the RCOG to create a Green Top guideline from it.

How should medical professionals react to impacted fetal head?

The June 2023 RCOG paper provides an algorithm on how to manage this obstetric emergency.

  • Anticipation of IFH is important where there are clinical features including a low position of the fetal head, the malposition of the fetal head (for example the baby is in a “back to back” position), advanced cervical dilatation and a failed assisted vaginal birth.
  • If IFH is anticipated then clinical staff can prepare for the caesarean section in a better way so that it’s ensured senior and experienced staff are present, attempts to move the fetal head are made pre making an incision and the anaesthetist has GTN spray ready to reduce uterine contractions.
  • Diagnosis of impacted fetal head.
  • Declaration of an emergency ensures clear communication and calmer consideration of how to manage a stressful emergency situation.
  • Neonatal staff can be called ready for neonatal resuscitation if required.

When impacted fetal head is identified, there are a number of ways to manage it.

What is abdominal cephalic disimpaction?

This is when the obstetrician places their hand into the abdominal incision to access the fetal head by cusping the fetal head anteriorly against the maternal pubic symphysis bone. This is a very skilled technique whereby the surgeon needs to achieve the safe flexion of the fetal head to elevate the head sufficient to enable delivery. If this fails then the ‘push technique’ should be attempted:

What is the push technique in impacted fetal head?

If on caesarean section the head cannot be delivered abdominally the obstetrician or midwife can attempt to delivery the fetal head by placing their hand into the vagina to gently attempt to disengage the head from the pelvis and push the impacted fetal head up into the uterus to allow for caesarean delivery.

This in itself is quite high-risk procedure and requires excellent communication between the surgeon and the medic pushing on the fetal head. There is a risk of not only excessive pressure causing skull injury to the fetus but also the risk of worsening the impaction by causing the head to become more deflexed and embedded.

What is a Reverse Breech extraction?

Having considered inverted T or J incision of the abdomen, a reverse breech extraction involves the obstetrician inserting their hand into the upper section of the uterus in order to grasp the fetal foot or feet – this is followed by steady traction of the fetal feet towards the mother’s feet to flex the fetal waist and deliver first the legs and then buttocks, followed by the fetal head.

What is the reverse Patwardhan technique?

This is a modification of the reverse breech extraction, where the arms rather than the feet are delivered first. This is not a recommended technique in the UK.

Why are cases of impacted fetal head on the rise?

There are a number of theories in circulation, aiming to explain why impacted fetal head is on the rise. They include:

  • increasing rates of induction of labour;
  • changes in how deliveries are managed;
  • an increase in caesarean sections being performed at a late stage of labour, once the mother is more fully dilated; and
  • a lack of consistent training and management protocols for impacted fetal head.

recent study looking at the incidence of impacted fetal head at caesarean section revealed that impacted fetal head is most commonly encountered when cervical dilation was greater than eight centimetres.

A lack of consistent training and management protocols for impacted fetal head could also be an issue. A survey led by the obstetric team at Southmead Hospital in Bristol revealed that although 98% of UK obstetricians had encountered impacted fetal head, but over 10% of them had not received any training on how to address it.

The ENS report recommends that further research is required to understand the cause of impacted fetal head/difficult delivery of the fetal head at caesarean section and to develop standardised management of the situation.

It is hoped that further research will be funded to enable UK research teams to put forward sufficient evidence for the RCOG to create a Green Top Guideline on the management of IFH and embed management of this emergency into full multidisciplinary training for maternity clinicians.

The consequences of prolonged oxygen deprivation (due to delay in delivery) or crushing injuries to the fetal skull can be severe with life long neurological injuries, including cerebral palsy.

Mothers can often suffer severe tissue injury and long term impact on their fertility as well as psychiatric harm caused by a traumatic birth.

Has your child experienced a birth injury?

If you want to find out more about making a claim for compensation, please contact our enquiries team who can help you to understand your options.

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