Techniques for managing an impacted fetal head at caesarean section: A systematic review

Anaesthetic considerations for impacted fetal head at caesarean delivery: a focused review

BACKGROUND

Impacted fetal head occurs when the fetal head is deeply engaged within the maternal pelvis and difficult to deliver during caesarean delivery. In order to deliver the fetal head, additional surgical manoeuvres and/or pharmacological tocolysis are needed. The aim of this focused review is to outline the incidence, risk factors, management and complications of this obstetric emergency from the perspective of the anaesthetist.

METHODS

Databases were searched for free text headings and subject headings associated with different permutations of terms related to impacted fetal head and caesarean delivery.

RESULTS

Impacted fetal head has been estimated to occur in 1.5 % of elective caesarean deliveries and 2.9-18.4% of all emergency caesarean deliveries at any cervical dilatation. Risk factors include advanced cervical dilatation, labour augmentation with oxytocin, prolonged second stage of labour, fetal malposition and junior grade of operating obstetrician. If impacted fetal head occurs, the anaesthetist in conjunction with the multidisciplinary team should consider decreasing the height of the operating table, providing a step for the obstetrician to stand on, placing the patient in the head down position, providing pharmacological tocolysis with glyceryl trinitrate (or nitroglycerin), beta-2 adrenoreceptor agonists or volatile anaesthetic agents, and managing complications such as postpartum haemorrhage.

CONCLUSION

Impacted fetal head is an obstetric emergency that the anaesthetist should be familiar with and has a vital role in managing. We propose an algorithm for management that may serve as a clinical decision aid.

Impacted fetal head at cesarean delivery

PURPOSE

Impacted fetal head (IFH) can be defined as the deep engagement of the fetal head in the maternal pelvis at the time of cesarean delivery that leads to its difficult or impossible extraction with standard surgical maneuvers. In this narrative review, we aimed to ascertain its incidence, risk factors, management and complications from the perspective of the anesthesiologist as a multidisciplinary team member.

METHODS

Databases were searched from inception to 24 January 2023 for keywords and subject headings associated with IFH and cesarean delivery.

RESULTS

IFH has an incidence of 2.9-71.8 % in emergency cesarean section. Maternal risk factors are advanced cervical dilatation, second stage of labor and oxytocin augmentation. Anesthetic and obstetric risk factors include epidural analgesia and trial of instrumental delivery and junior obstetrician, respectively. Neonatal risk factors are fetal malposition, caput and molding. Current evidence indicates a lack of confidence in the management of IFH across the multidisciplinary team. Simple interventions in IFH include lowering the height or placing the operating table in the Trendelenburg position, providing a step for the obstetrician and administering pharmacological tocolysis. Maternal complications are postpartum hemorrhage and bladder injury while neonatal complications include hypoxic brain injury, skull fracture and death. Surgical complications are reviewed to remind the anesthesiologist to anticipate and prepare for potential problems and manage complications in a timely manner.

CONCLUSION

The anesthesiologist has a fundamental role in the facilitation of delivery in IFH. We have proposed an evidence based management algorithm which may be referred to in this emergency situation.

Management of impacted fetal head at cesarean birth: A systematic review and meta-analysis

INTRODUCTION

Despite increasing incidence of impacted fetal head at cesarean birth and associated injury, it is unclear which techniques are most effective for prevention and management. A high quality evidence review in accordance with international reporting standards is currently lacking. To address this gap, we aimed to identify, assess, and synthesize studies comparing techniques to prevent or manage impacted fetal head at cesarean birth prior to or at full cervical dilatation.

MATERIAL AND METHODS

We searched MEDLINE, Emcare, Embase and Cochrane databases up to 1 January 2023 (PROSPERO: CRD420212750016). Included were randomized controlled trials (any size) and non-randomized comparative studies (n ≥ 30 in each arm) comparing techniques or adjunctive measures to prevent or manage impacted fetal head at cesarean birth. Following screening and data extraction, we assessed risk of bias for individual studies using RoB2 and ROBINS-I, and certainty of evidence using GRADE. We synthesized data using meta-analysis where appropriate, including sensitivity analyses excluding data published in potential predatory journals or at risk of retraction.

RESULTS

We identified 24 eligible studies (11 randomized and 13 non-randomized) including 3558 women, that compared vaginal disimpaction, reverse breech extraction, the Patwardhan method and/or the Fetal Pillow®. GRADE certainty of evidence was low or very low for all 96 outcomes across seven reported comparisons. Pooled analysis mostly showed no or equivocal differences in outcomes across comparisons of techniques. Although some maternal outcomes suggested differences between techniques (eg risk ratio of 3.41 [95% CI: 2.50-4.66] for uterine incision extension with vaginal disimpaction vs. reverse breech extraction), these were based on unreliable pooled estimates given very low GRADE certainty and, in some cases, additional risk of bias introduced by data published in potential predatory journals or at risk of retraction.

CONCLUSIONS

The current weaknesses in the evidence base mean that no firm recommendations can be made about the superiority of any one impacted fetal head technique over another, indicating that high quality training is needed across the range of techniques. Future studies to improve the evidence base are urgently required, using a standard definition of impacted fetal head, agreed maternal and neonatal outcome sets for impacted fetal head, and internationally recommended reporting standards.

Difficult fetal extraction in cesarean section: Number 8 - 2024

The main causes of difficult fetal extraction during cesarean section are deeply impacted fetal head and floating presentation of the fetus. Studies of management techniques for difficult fetal extraction during cesarean section and the maternal and neonatal results lack scientific evidence, as these predominantly come from case reports, small case series and expert opinions. The deeply impacted fetal head is usually associated with prolongation of the expulsion period and/or unsuccessful attempts at operative vaginal delivery. The main maternal complications associated with the management of the deeply impacted fetal head are lacerations in the lower uterine segment, hematomas in the uterine ligaments and injuries to the uterine vessels, cervix and/or urinary tract. The main neonatal complications associated with the management of a deeply impacted fetal head are intracranial hemorrhage, fractures of the skull and/or cervical spine, nerve injuries, perinatal asphyxia and even death. Among the maneuvers for delivery of the deeply impacted fetal head, the abdominovaginal delivery (push method) seems to be the most associated with maternal and neonatal complications. In the non-insinuated and floating fetal head, the internal podalic version followed by pelvic extraction differs from the reverse breech extraction (pull method). When the fetal head is high in the pelvis, the fetus is internally ejected before the extraction of its body segments, similar to the internal version performed in the vaginal delivery of the second twin with floating presentation of the fetus.

Impacted fetal head extraction methods at second stage cesarean and subsequent preterm delivery: A multicenter study

OBJECTIVE

Second-stage cesarean delivery (CD) is associated with subsequent preterm birth (PTB). It has been suggested that an increased risk of PTB after second-stage cesarean delivery could be linked to a higher chance of cervical injury due to the extension of the uterine incision. Previous studies have shown that reverse breech extraction is associated with lower rates of uterine incision extensions compared to the "push" method. We aimed to investigate the association between the method of fetal extraction during second-stage CD and the rate of spontaneous PTB (sPTB), as well as other maternal and neonatal outcomes during the subsequent pregnancy.

METHODS

This was a multicenter retrospective cohort study. The study population included women in their first subsequent singleton delivery following a second-stage CD between 2004 and 2021. The main exposure of interest was the method of fetal extraction in the index CD ("push" method vs. reverse breech extraction). The primary outcome of this study was sPTB <37 weeks in the subsequent pregnancy. Secondary outcomes were overall PTB, trial of labor, and other adverse maternal and neonatal outcomes. Univariate analysis was followed by multiple logistic regression modeling.

RESULTS

During the study period, 2969 index CD during second stage were performed, of those 583 met the inclusion criteria, of whom 234 (40.1%) had fetal extraction using the reverse breech extraction method, while 349 (59.9%) had the "push" method for extraction. In univariate analysis, women in those two groups had statistically similar rates of sPTB (3.7% vs. 3.0%; odds ratio [OR] 1.25, 95% CI: 0.49-3.19) and overall PTB (<37, <34 and <32 weeks), as well as other maternal, neonatal, and trial of labor outcomes. This was confirmed by multivariate analyses with an adjusted OR of 1.27 (95% CI: 0.43-3.71) for sPTB.

CONCLUSION

Among women with a previous second-stage CD, no significant difference was observed in PTB rates in the subsequent pregnancies following the "push" method compared to the reverse breech extraction method.

Circumferential Vaginal Tear During the Cesarean Section: A Complication of Vaginal Hand Assistance in a Deeply Impacted Fetal Head

We present the case of a 29-year-old, G2P1+0 pregnant woman who was unbooked and presented to the emergency room at 36+5 weeks gestation with complaints of leaking liquor, labour pains, vaginal bleeding and raised blood pressure. Her history revealed previous vaginal delivery and index pregnancy complicated with obstetric cholestasis, pre-eclampsia, and fetal growth restriction. During her hospital course, the patient underwent an emergency cesarean section due to uncontrolled blood pressure and pathological cardiotocograph (CTG) revealing a deeply impacted fetal head intraoperatively and necessitating an inverted T incision on the uterus. Although the newborn was delivered successfully, a full-thickness circumferential tear in the vaginal vault was discovered, requiring immediate surgical repair with the involvement of a urologist. The patient experienced postoperative complications related to pre-eclampsia and sepsis but was eventually discharged in stable condition. This case highlights the importance of prompt diagnosis and management of obstetric emergencies especially in the case of deeply impacted fetal head, and the need for a multidisciplinary approach to address complications such as vaginal tears during cesarean sections due to vaginal assistance in delivering the baby.

Management of Impacted Fetal Head at Caesarean Birth: Scientific Impact Paper No. 73

Over one-quarter of women in the UK have a caesarean birth (CB). More than one in 20 of these births occurs near the end of labour, when the cervix is fully dilated (second stage). In these circumstances, and when labour has been prolonged, the baby's head can become lodged deep in the maternal pelvis making it challenging to deliver the baby. During the caesarean birth, difficulty in delivery of the baby's head may result - this emergency is known as impacted fetal head (IFH). These are technically challenging births that pose significant risks to both the woman and baby. Complications for the woman include tears in the womb, serious bleeding and longer hospital stay. Babies are at increased risk of injury including damage to the head and face, lack of oxygen to the brain, nerve damage, and in rare cases, the baby may die from these complications. Maternity staff are increasingly encountering IFH at CB, and reports of associated injuries have risen dramatically in recent years. The latest UK studies suggest that IFH may complicate as many as one in 10 unplanned CBs (1.5% of all births) and that two in 100 babies affected by IFH die or are seriously injured. Moreover, there has been a sharp increase in reports of babies having brain injuries when their birth was complicated by IFH. When an IFH occurs, the maternity team can use different approaches to help deliver the baby's head at CB. These include: an assistant (another obstetrician or midwife) pushing the head up from the vagina; delivering the baby feet first; using a specially designed inflatable balloon device to elevate the baby's head and/or giving the mother a medicine to relax the womb. However, there is currently no consensus for how best to manage these births. This has resulted in a lack of confidence among maternity staff, variable practice and potentially avoidable harm in some circumstances. This paper reviews the current evidence regarding the prediction, prevention and management of IFH at CB, integrating findings from a systematic review commissioned from the National Guideline Alliance.