Management of impacted fetal head at caesarean section − Current practice and future development
Caesarean sections (CS) are on the rise globally and worldwide one in five women deliver by CS. This trend includes increased in-labour and full dilatation caesarean section. In the UK, emergency caesarean sections (EMCS) constitute almost one quarter of all deliveries and 6 % are at full dilatation (FDCS), with similar trends seen in other countries. The reasons for this are multifactorial. Changes in professional training and practice are underlying factors, especially the reported decrease in experience and skills in performing assisted vaginal de liveries. Social and cultural expectations also contribute, and the decision for caesarean section may be maternally driven.
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
