Management of impacted fetal head at caesarean section − Current practice and future development

Caesarean section is perceived by the public as a procedure
which is safer for the mother and the baby; some women may request a caesarean
section in labour over an assisted vaginal delivery. A full dilatation
caesarean section can be technically challenging and is associated with greater
risks. The fetal head is lower and can be wedged within the maternal pelvis
making it more difficult to deliver, a situation known as ‘impacted fetal
head’. This is associated with increased maternal and neonatal morbidity
including uterine extensions, haemorrhage, fetal trauma and hypoxic ischaemic
encephalopathy. Moreover as an obstetric emergency it is a clinical scenario
which is extremely stressful for the patients, their partners and the healthcare
professionals involved. Impacted fetal head (IFH) is being increasingly
reported by medical professionals. It has been associated with coroner
inquiries and litigation. There has been a drive for a greater understanding of
this condition and the optimum strategies for its management, including the
innovation of novel devices to facilitate delivery. This paper reviewed this
issue and its current management techniques, with a focus on de vices for
disimpaction of the fetal head as well as highlighting areas for further
research.

Complications

IFH is associated with increased maternal and neonatal
complications. Immediate intra-operative complications include extensions of
the uterine incision, haemorrhage, bladder, and ureteric injury. There is an
increased need for maternal blood transfusion. Moreover, emerging evidence suggests
that in-labour and FDCS are associated with a risk of recurrent mid-trimester
loss and spontaneous preterm birth in subsequent pregnancies.

The exact underlying mechanism is not yet known but it may
be related to damage to cervix at the time of caesarean section. This damage
may be caused the lower segment incisions inadvertently made into cervical
tissue, or by traumatic extensions from the incision site. This is more likely
to occur with an in-labour or fully dilated caesarean section when anatomy can
be more difficult to delineate as the tissues are more likely to be oedematous
and the cervix becomes continuous with lower segment and drawn up over the
presenting part. Traditional teaching is to make the uterine incision higher to
avoid this complication, however, this may increase the difficulty of
delivering the head as the operator’s hand is a greater distance from the fetal
head. Difficulty delivering the fetal head increases the risk of fetal trauma
including skull fractures, subgaleal and intracranial haemorrhage. The
associated delay in the birth of the baby, especially if there was presumed
compromise prior to the CS, may lead to hypoxic ischaemic encephalopathy and
rarely, perinatal death. In view of the serious sequalae associated with
impacted fetal head, it follows that there are significant medicolegal
consequences associated with this condition.

Management

IFH is an obstetric emergency and should be managed with a
multidisciplinary approach. It is important that the situation is declared to
ensure a shared understanding within the team. Skills such as escalation, clear
communication, and task delegation, should be employed as in other intrapartum
emergencies. It is key for the operating obstetrician to achieve flexion of the
fetal head to be able to disimpact it. An antero-lateral approach is recommended
to allow the operator to get their hand below the fetal head. The head should
then be elevated towards the uterine incision, in a controlled manner avoiding
excess pressure to the lower segment and uterine angles to minimise extensions,
which can be accomplished by keeping the arm straight. Some find it easier to
flex and elevate the fetal head with the non-dominant hand.

It is important to ensure that the operating table is at an
appropriate height, so this should be adjusted as necessary with a head down
tilt employed as needed and a step should be available if required. In
addition, tocolysis to relax the uterine muscle may facilitate disimpaction,
and the use of glyceral trinitrate (GTN), salbuatol and terbutaline have been
reported, with GTN the most used. There is no robust evidence to support
tocolysis in this context, however anecdotal evidence suggests that it is
beneficial. It should be recognised that tocolytics are associated with an
increased risk of postpartum haemorrhage by causing uterine atony, a
complication which is already more likely to occur with impacted fetal head and
in labour caesarean section tending the uterine incision may be required if
there is insufficient access or a risk of unintentional extensions. Either an
inverted T or J incision can be performed.

Additional manoeuvres

In addition to the techniques described above, several
additional manoeuvres have been described to facilitate disimpaction of the
fetal head – vaginal disimpaction, reverse breech extraction and Patwhardan
method.

Vaginal disimpaction, or ‘push’ method, involves an
assistant placing the whole hand into the vagina and applying pressure across
the fetal head to flex it. To achieve adequate vaginal access the woman’s legs
should be repositioned in semi-lithotomy with the knees flexed and thighs
abducted. An association between vaginal disimpaction and perinatal skull
fracture has been described. This may be due to poor technique, including using
two fingers instead of the whole hand, which causes fetal trauma.

Reverse breech, one
‘pull’ method, involves grasping the feet through the uterine incision first
and then delivering by breech extraction. Reports have suggested that
delivering babies by reverse breech extraction may increase the risk of limb
injury, including femoral or humeral fractures. Patwardhan manoeuvre, another
‘pull’ method, is a modification of reverse breech extraction, where the arms
are delivered first. Following delivery of both arms through the incision,
gentle traction is applied via the axilla to flex the abdomen and deliver the
breech, following which the head is lifted out of the pelvis. It has been
suggested that this technique is beneficial in cases when the feet are
difficult to access, such as when the fetal head is occipto-anterior. It is
more commonly practiced in India where it was developed and is not part of
current training for UK obstetricians.

The evidence for the effectiveness of these additional
manoeuvres is very limited. Systematic reviews suggest that ‘pull’ methods,
reverse breech extraction and Patwardhan method, may be associated with
improved maternal outcomes compared with vaginal disimpaction. Patwardhan
method is associated with less operative blood loss, length of operative time
and uterine extension compared vaginal disimpaction. Both reverse breech and
Patwardhan method were associated with less uterine extensions. There is little
data on any improved outcomes for the infant. There is significant
heterogeneity in the methodology of the existing studies, making comparison
difficult. Moreover, many of the studies are observational, meaning there is a
high risk of bias. Therefore, it is not difficult to derive firm conclusions
regarding the superiority of one technique over another.

Disimpaction devices

There is a lack of consensus regarding which method for disimpaction
is safest and most effective, and in some cases multiple techniques are
required. This clinical dilemma has led to the innovation of medical devices to
aid in the disimpaction of the fetal head, namely the Fetal Pillow® and Tydeman
Tube.

The Fetal Pillow® is a soft silicone balloon that is
inserted vaginally, before starting the caesarean section. It is inflated to
elevate the fetal head. It is intended for use when performing a caesarean
section with a deeply engaged head, at a fetal station at or below the ischial
spines or following an unsuccessful assisted vaginal birth. The evidence for
the Fetal Pillow® is limited and there is a paucity of high-quality data
establishing the efficacy of the device. One systematic review suggests that
the Fetal Pillow® reduces the time from uterine incision to birth, compared to
no pillow. It is also associated with reduced rate of uterine extension,
compared to no pillow.

The evidence about operative blood loss is conflicting, with
some studies suggesting an increased incidence of postpartum haemorrhage with
Fetal Pillow® while others suggesting a decrease. Similarly, one meta-analysis
found equivocal findings for differences in risk of infant birth trauma, Apgar
scores or NICU admission with the use of the The Fetal Pillow® while another
suggested there were less admissions to NICU. The evidence for Fetal Pillow®
must be interpreted with caution, as the studies are heterogenous. Also, many
of the studies are at serious risk of bias and provide low or very low
certainty of evidence. Following the retraction of this paper, NICE are
currently reviewing the guidance for use of this device in clinical practice.

The Tydeman® Tube is a single-use hollow silicone tube with
a round cup inserted vaginally to elevate the fetal head. It is designed to
minimise pressure applied to the fetal head and reduce any suction effect once
access has been achieved. It can be placed in the vagina prior to surgery if
the fetal head is thought to impacted or can be inserted intra-operatively if
difficulty is encountered. Several studies have demonstrated that the Tydeman®
Tube achieves greater elevation of the fetal head compared to vaginal dis impaction
and fetal pillow. The force applied with the Tydeman® Tube is higher, however
it has been demonstrated that the area of contact with the Tydeman® Tube is
four-fold greater than the area achieved using digital disimpactation, therefore
the pressure applied to the fetal head is less overall. These studies were performed
on caesarean section simulators for impacted fetal head. There have been few
studies of the Tydeman® Tube in clinical practice, however a small case series
demonstrated that operators found the de vice efficacious and easy to use, with
no adverse maternal and neonatal events attributed to the use of the device.

The future

Overall, there is a lack of high-quality evidence comparing
techniques to manage IFH at caesarean. Well-designed, adequately powered trials
are required. In addition, there is a need for robust evidence for both
disimpaction devices and a randomised control trial to directly compare the
Fetal Pillow® and Tydeman® Tube should be undertaken. Existing studies focus on
women undergoing FDCS but with emerging evidence that half of the cases of IFH
are reported during caesarean delivery at less than full dilatation, the
management of this clinical situation is another area for future research. Finally,
in addition to improving the evidence base, it is essential that clinicians are
familiar with the various techniques to manage IFH effectively and reduce
associated complications.

At present UK trainees and consultant labour ward leads
report that current training is ‘inconsistent and inadequate’, and it is a
clinical scenario not currently taught in midwifery curriculum. Findings from a
new, practical course which was developed for training in complex deliveries
including impacted fetal head at caesarean section, found that hands-on
training improved middle and senior grade trainees’ confidence in managing this
condition. Simulation-based training is likely to provide an effective and safe
form of training, and to this effect several high-fidelity simulators have been
developed. Simulation-based training also offers clinicians an opportunity to
develop their team working and communication skills. An algorithm for the
management of impacted fetal head has been developed to improve performance in
simulation-based training and real-life scenarios. This could be embedded into
local and regional training programs.

Impacted fetal head is an unpredictable obstetric emergency
with the potential to have devastating consequences for mother and baby. It not
only contributes significantly to maternal and neonatal morbidity but has
serious psychological, litigious and economic implications. In view of its
increasing prevalence, high-quality research into management techniques, including
disimpaction devices, is required to drive the development of evidence-based
practice. Moreover, obstetric and midwifery training should embed the skills to
manage impacted fetal head to facilitate optimum management of this important
clinical condition.

Source: L. van der Krogt et al.; European Journal of
Obstetrics & Gynecology and Reproductive Biology 307 (2025) 170–174