Feasibility of a RCT of techniques for managing an impacted fetal head during emergency caesarean section: the MIDAS scoping study

Background: Second-stage caesarean sections, of which there are around 34,000 per year in the UK, have greater maternal and perinatal morbidity than those in the first stage. The fetal head is often deeply impacted in the maternal pelvis, and extraction can be difficult. Numerous techniques are reported, but the superiority of one over another is contentious and there is no national guidance. Objective To determine the feasibility of a randomised trial of different techniques for managing an impacted fetal head during emergency caesarean. Design A scoping study with five work packages: (1) national surveys to determine current practice and acceptability of research in this area, and a qualitative study to determine acceptability to women who have experienced a second-stage caesarean; (2) a national prospective observational study to determine incidence and rate of complications; (3) a Delphi survey and consensus meeting on choice of techniques and outcomes for a trial; (4) the design of a trial; and (5) a national survey and qualitative study to determine acceptability of the proposed trial. Setting Secondary care. Participants Health-care professionals, pregnant women, women who have had a second-stage caesarean, and parents. Results Most (244/279, 87%) health-care professionals believe that a trial in this area would help guide their practice, and 90% (252/279) would be willing to participate in such a trial. Thirty-eight per cent (98/259) of parents reported that they would take part. Women varied in which technique they thought was most acceptable. Our observational study found that impacted head is common (occurring in 16% of second-stage caesareans) and leads to both maternal (41%) and neonatal (3.5%) complications. It is most often treated by an assistant pushing the head up vaginally. We designed a randomised clinical trial comparing the fetal pillow with the vaginal push technique. The vast majority of health-care professionals, 83% of midwives and 88% of obstetricians, would be willing to participate in the trial proposed, and 37% of parents reported that they would take part. Our qualitative study found that most participants thought the trial would be feasible and acceptable. Limitations Our survey is subject to the limitation that, although responses refer to contemporaneous real cases, they are self-reported by the surgeon and collected after the event. Willingness to participate in a hypothetical trial may not translate into recruitment to a real trial. Conclusions We proposed a trial to compare a new device, the fetal pillow, with a long-established procedure, the vaginal push technique. Such a trial would be widely supported by health-care professionals. We recommend that it be powered to test an effect on important short term maternal and baby outcomes which would require 754 participants per group. Despite the well-known difference between intent and action, this would be feasible within the UK. Future work We recommend a randomised controlled trial of two techniques for managing an impacted fetal head with an in-built internal pilot phase and alongside economic and qualitative substudies. Study registration This study is registered as Research Registry 4942. Funding This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 6. See the NIHR Journals Library website for further project information. Plain language summary: One-quarter of UK pregnant women have a caesarean section. Most of these procedures are straightforward, but in a small number of cases unexpected complications can make the birth difficult. One complication, an impacted fetal head, may happen when caesarean sections are done in the second ‘pushing’ stage of labour. If the baby’s head is low and wedged in the woman’s pelvis, lifting it can be difficult, which can result in damage to the mother’s womb and vagina, and to her baby. Occasionally, babies die. There are different techniques doctors and midwives can use to make these births easier, but there is uncertainty around which is best. To plan a trial to test these techniques, we needed to know how often impacted head happens, what techniques are used to manage it and whether or not research is acceptable to parents and health-care professionals. We surveyed doctors and midwives to find out which techniques they use and what training they need. We surveyed parents and pregnant women and interviewed women who had experienced a second-stage caesarean. We collected information from UK hospitals to find out how common this is and the impact on women and babies. We found out the following: Around 7% of caesareans take place in second stage, and impacted fetal head occurs in 16% of these births. One-third of women would consent to take part in a trial, if the complication happened to them. Nearly all midwives and doctors thought that this research was important and would be willing to take part. Using all of the information we collected, we designed a clinical trial. We wanted to compare two techniques for managing an impacted fetal head. The first is the vaginal push technique, where the doctor or midwife puts their hand into the mother’s vagina to push her baby’s head up, and the second is the fetal pillow, a device inserted into the mother’s vagina before the operation starts to dislodge the baby’s head upwards. Scientific summary: Background Emergency caesarean section (CS) performed in the second stage of labour, which occurs in 34,000 births per annum in the UK, has greater perinatal and maternal morbidity than CS performed in the first stage. Second-stage CS may be complicated by the fetal head being deeply impacted in the maternal pelvis, which occurs in 1.5% of all emergency CSs. Complications include longer delivery times, uterine tears, injury to the baby and even, albeit rarely, death. Numerous techniques to assist in delivery of an impacted fetal head (IFH) are reported. The superiority of one technique over another is contentious. At present, there is no national guidance on what techniques to employ. Research questions What are the current practice, level of experience and training requirements for managing an IFH during emergency CS among UK obstetricians, obstetric anaesthetists and midwives? What are the views of pregnant women and their partners on research in this area? How acceptable is a randomised trial in this area to women who have experienced a second-stage caesarean birth, and what are their views on the different proposed techniques for managing an IFH? What is the incidence of IFH and maternal and neonatal complications arising from IFH in the UK? What techniques and outcomes do health-care professionals and parents think should be included in a randomised trial in IFH? What should the design be for a randomised trial in IFH? How acceptable is the randomised trial we have designed to health-care professionals, women who have experienced a second-stage caesarean birth and pregnant women? Methods We undertook a national survey of obstetricians, trainee obstetricians, obstetric anaesthetists and midwives to determine current practice, level of experience and training requirements for managing IFH during emergency CS. We also undertook a national survey of parents to determine their views on this topic. Individual face-to-face interviews with women who have experienced a second-stage CS were carried out to determine the acceptability of a randomised trial in this area and their views on the different proposed techniques for managing IFH. A national, prospective UK Obstetric Surveillance System (UKOSS) surveillance study was undertaken to determine the incidence and consequences of IFH in the UK. Based on the findings of previous work packages, we conducted a Delphi survey followed by a virtual consensus meeting of experts and important stakeholders to decide which techniques should be tested in any trial and which outcomes should be included. A randomised trial of different techniques for managing IFH during emergency CS was designed. We undertook a national survey of lead obstetricians, pregnant women and midwives to determine the feasibility and acceptability of the randomised trial designed. Three sets of individual telephone or video interviews were carried out with lead obstetricians/senior obstetric trainees, women who have experienced a second-stage CS and primiparous women to determine the acceptability and feasibility of the planned trial. Results The majority (89%) of health-care professionals stated that a clinical trial in this area would help to guide their clinical practice, and 87% would be willing to participate in such a trial. In addition, 37% of parents reported that they would be either likely or very likely to take part, or neutral. Women varied in which technique they thought was most acceptable, and their trust in medical expertise and prioritising the safety of the baby were important moderators of acceptability. Our national prospective observational study found that impacted head is common, occurring in 16% of second-stage caesarean births in the UK, and leads to both maternal and neonatal complications. Overall, 230 (41%) women and 20 babies (3.5%) experienced complications. Thirteen babies (2%) died or sustained severe injury. Seven suffered bony fracture, two brachial plexus injury and one facial palsy. Three had moderate or severe hypoxic ischaemic encephalopathy, and seven were cooled. Four babies died: one prior to the caesarean, one with multiple abnormalities and two as a direct result of complications caused by IFH. IFH is currently most often treated by an assistant pushing the head up vaginally during the CS. Data from earlier work packages were used throughout the project, culminating in the design of a randomised clinical trial. Our proposed trial would compare a new device, the fetal pillow, with a procedure used for many years, the vaginal push technique, for preventing IFH. Most doctors and midwives believed that such a trial would be important and were willing to recruit participants to one. About one in three women said that they would be willing to join such a trial. The only interventions that were more popular with patients were tocolysis and the head-down technique. Both of these are adjunct techniques used by all obstetricians and, therefore, are not suitable for evaluation in a trial. The required sample size of such a trial depends on whether it is powered to show a difference in severe maternal morbidity (control event rate 2.3%, 4698 participants per group), a difference in fetal short-term morbidity (control event rate 13.7%, 754 participants per group) or only a difference in less severe maternal events, including haemorrhage over 1000 ml (control event rate 27%, 322 participants per group). We believe that it is not feasible to conduct the trial powered on severe maternal morbidity. However, parents and doctors believe that a trial to test the effect of different procedures on meaningful baby outcomes is important. We therefore recommend that the required sample size would be 754 per group. The vast majority of midwives (83%) and obstetricians (88%) would be willing to participate in the clinical trial proposed. In addition, 37% of parents reported that they would be either likely or very likely to take part, or neutral. Our qualitative study found that most participants thought that the trial would be feasible and acceptable. Conclusions We recommend that a randomised trial with an internal pilot phase comparing a new device, the fetal pillow, with a procedure used for many years, the vaginal push technique, for managing IFH be conducted. This trial is widely supported by health-care professionals. We recommend that the definitive trial be powered to test an effect on important short-term maternal and baby outcomes, which would require 754 participants per group. A sufficient number of women would be willing to be join such a trial to make it likely to be feasible in the UK. Study registration This study is registered as Research Registry 4942. Funding This project was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 27, No. 6. See the NIHR Journals Library website for further project information.