No method best to achieve delivery for Impacted fetal head during second stage of CS: EJOG
Caesarean section rates are increasing in countries. At least 5% are performed at full cervical dilatation (in the second stage of labour) and this proportion is rising. Both maternal and neonatal complications are greater during the second stage. One reason is that when the cervix is fully dilated, the baby's head may be deeply engaged in the pelvis, a so-called 'impacted fetal head'. Delivery in this situation may be technically challenging if the obstetrician cannot pass their hand between the bony maternal pelvis and the fetal head. A vacuum effect may also make head elevation difficult. The uterus is also typically thinned and stretched making extension of the uterine incision more likely. Complications for the baby include bony fractures, hypoxic brain injury and death. Risks of complications are further increased if there has been a prior unsuccessful attempt at instrumental birth.
Many different techniques have been advocated, including the Fetal Pillow; the Patwardhan method; the push technique; reverse breech extraction,tocolysis and the Tydeman tube but there are few data on how often they are used and which are most effective.
The aim of this study by N. Wyn Jones et al was to determine the incidence of, and complication rates from, impacted fetal head at full dilatation Caesarean birth in the UK, and record what techniques used are in use. This was performed as part of a wider scoping study commissioned by the National Institute for Health Research to determine the feasibility of designing a randomised trial comparing techniques for management of an impacted fetal head in the UK.
Prospective observational study using the UK Obstetric Surveillance System (UKOSS). Setting: 159 (82%) of the 194 UK hospitals with obstetric units. All women who underwent second stage Caesarean birth in the UK between 1st March and 31st August 2019. Further information was collected on cases where a dis-impaction technique was used, or the operating surgeon experienced 'difficulty' in delivering the head.
3,518 s stage Caesarean births were reported. The surgeon used a dis-impaction technique or reported 'difficulty' in 564 (16%) of these. The most common dis-impaction techniques used were manual elevation of the head by an assistant through the vagina (n = 235) and a fetal "pillow" (n = 176). Thirteen babies (2%) died or sustained severe injury. Four babies died (two directly attributable to the impacted fetal head).
Impacted fetal head is common and can result in significant maternal and neonatal complications. 6.1% of mothers require intensive care as a result of this condition which has not previously been reported. It is most often treated by an assistant pushing the head up vaginally during the Caesarean section.
Simulation based educational packages e.g. Desperate Debra, or theoretical introduction and algorithm use supported by simulation have demonstrated improvements in knowledge, skills and self confidence. The ALERT algorithm should be publicised. The Tydeman tube, is not currently in use as it is in the early stages of commercialisation but is an exciting development for the future.
"Although the emergency nature of the problem means that clinical trials will be challenging, successful emergency trials in labour are increasingly common. Further work is ongoing to decide whether a trial of different techniques of managing impacted head is feasible. In view of the increased use of anticipatory measures, any such trial should be undertaken promptly before evidence-free practice becomes embedded. There are promising new devices and proposed training algorithms for impacted fetal head which warrant further evaluation."
Source: N. Wyn Jones et al.; European Journal of Obstetrics & Gynecology and Reproductive Biology 272 (2022) 77–81
https://doi.org/10.1016/j.ejogrb.2022.03.004
