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Breech Presentation |
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This is an initial draft of some work I have been doing on breech presentation, it is incomplete but I thought it might be useful to some of you, until I get the final draft completed - Michelle It is widely recognised that there is higher perinatal mortality and morbidity with breech presentation, due primarily to prematurity, congenital malformations and birth asphyxia or trauma. Breech presentation, whatever the mode of delivery, is a signal for potential fetal handicap and this should inform management. Caesarean section for breech presentation has been suggested as a way of reducing the associated fetal problems and in many countries in northern Europe and North America caesarean section has become the normal mode of delivery in this situation. Introduction In my clinical experience I have encountered several women who have had a breech fetus at term, some of these had been diagnosed prior to labour and some as late as the second stage of labour. All of these women were recommended caesarean section and all took up that option. I felt these women did not have informed choice with regard to the method of birth for their breech babies, and as my knowledge was lacking in this area, I decided to look at the research and try to draw some conclusions. For this seminar I will be using part of the “five steps of evidence-based midwifery” adapted from Page (2000). Framing Clear Questions? I wanted to evaluate the research with regard to the safest method of delivery for a breech fetus at term. To help me to frame the question I used the table “Comparisons of good questions” adapted from Sackett et al (1997:27) In Page. This enabled me to divide the question into four components, the woman or problem, the intervention, the comparison intervention and the outcomes. Thus I formulated the following: “In women without other complications, with a singleton breech fetus presenting at term, will caesarean section or vaginal breech birth reduce perinatal and maternal morbidity and mortality?” I decided not to differentiate between primigravidae and multigravidae after looking at the literature as no studies made this distinction. Searching for the evidence I searched the Cochrane library for the relevant systematic reviews and meta-analyses. Then I searched the MIDIRS database, pubmed, medline, the internet and Coventry university library From the Cochrane library I attained The systematic review “Planned caesarean section for term breech delivery” this included 3 studies these will provide the main components of this seminar. The MIDIRS search uncovered more studies and some expert comments these are beyond the scope of this review but will be referred to in the reflection. The Confidential enquiry into stillbirths and deaths in infancy, in its 7th annual report focuses on breech presentation. This information will also be included in this discussion. In 2 studies from the same unit, women with frank (Collea et al, 1980) or non-frank (Gimovsky et al, 1983) breech presentations at term were allocated by random selection to a policy of elective caesarean section or a protocol allowing vaginal delivery within certain limitations such as an adequate pelvis as measured by X-ray pelvimetry. It is not clear how randomisation was achieved. Both studies used partial breech extraction with use of Piper forceps Collea et al (1980) carried out a prospective study of 208 women in labour at term with singleton fetuses in a frank breech presentation. 115 women were randomised to vaginal delivery group and 93 to elective caesarean section group. It is not clear what methods of statistical analysis have been used if any. Gimovsky et al (1983) undertook a prospective study of 105 women with a non-frank breech presentation at term. 70 were randomised to trial of labour and 35 to elective caesarean section. Statistical analysis was by the chi-squared test and Fischer exact tests. Both studies found that caesarean section substantially increased maternal morbidity and that carefully selected and managed term breech fetuses will have neonatal morbidity at vaginal delivery similar to that seen at caesarean section. Both stated that caesarean section is required liberally in breech presentation, but that selective management was safe. The studies by Collea et al (1980) and Gimovsky et al (1983) are both 20 years old, have very small sample sizes and were carried out in only one unit, thus they are of limited value. Consequently is seems that there has only ever been one trial that can be examined to answer the question as to the safest way to deliver a term breech – The Term Breech Trial. So this is what we shall focus on assessing. The Term Breech Trial (Hannah et al, 2000) was a large, multi-centre trial. It was conducted in 26 countries with 2088 women with a singleton fetus in a frank or complete breech presentation at term. Women were randomly assigned planned caesarean section or planned vaginal birth. Women having a vaginal breech delivery had an experienced clinician at the birth. And Women were followed up at 6 weeks post-partum. The researchers concluded that perinatal mortality, neonatal mortality or serious neonatal morbidity was significantly lower for the planned caesearean section group than for the planned vaginal birth group (1.6% vs 5%) and that there were no differences between groups in terms of maternal mortality or serious maternal morbidity (3.9% vs 3.2%). Assessing the evidence There are inarguable strengths of the trial, including its large sample size and randomisation. If you look at The outcome and results columns in this table they are copied exactly as produced in the trial. If you look at the results tables it appears obvious that caesarean section is safer than vaginal birth but this is not necessarily the case. Firstly the results given in the vaginal birth group are for everyone who was in that group regardless of whether the had a caesarean or vaginal birth so we cannot see if the mortality or morbidity is caused by mode of delivery or other factors such as poor care in labour. The results are presented in this way throughout the study and make an analysis difficult. It makes the study a trial of using only one mode of delivery without the use of clinical judgement which is not appropriate. VALIDITY To what extent is the study measuring the impact of vaginal birth and caesarean section on fetal and maternal mortality and morbidity? Or is it measuring something else. All of the studied vaginal births were medically managed- with a 64.7% of the women being induced or augmented with drugs, 46.3% having epidurals, and 22.4% having their membranes artificially ruptured. It may be that these interventions that did not happen in the planned caesarean group were the cause of the problems. The study may have been measuring iatrogenic difficulties and these factors should have been controlled for. The medical literature frequently acknowledges doctors lack expertise in vaginal breech birth (Thornton and Hayman, 2002). Obstetric training schemes are inadequate due to the proliferation of delivery by elective Caesarean section which means doctors are simply not able to develop the skills necessary for safe vaginal breech birth. The Trial stipulated the need for “skilled and experienced clinicians” to be present at birth but the trial was also used as a teaching time for less experienced practitioners.[8] Reminders were published about the need for expertise in regular newsletters [10] when it became clear there were no experienced clinicians available at some births [9] (2.6% in the whole study). The report [11] notes reduced benefit of Caesarean section in some countries - the authors speculate this is “possibly because of higher levels of experience with vaginal breech delivery in those countries”. Newborn outcomes at vaginal birth necessarily depend on the expertise of the birth attendant. Overly forceful, hasty, or ill-judged manipulations can cause serious birth injuries or birth asphyxia. On paper, at least, the researchers had ensured that obstetricians attending vaginal breech births were experienced with them. If you read the bulletins sent to the hospitals involved in the trial. It becomes clear that the increasingly detailed instructions and warnings as the trial progressed indicate that, in fact, some of the attending obstetricians lacked the requisite skills. It may be that many of the serious newborn complications occurred at only one or two of the participating institutions. This would indicate that the problems experienced with vaginal breech related to the competency and experience of the birth attendants, not vaginal breech per se. The researchers chose not to report outcomes on a site-by-site basis, so we do not know if this is the case. The study was conducted in 26 countries with a marked heterogeneity of patient characteristics, technical sophistication and perinatal mortality rates, so can we sa that results obtained from a less developed country are applicable to the UK? Also many aspects of clinical care were imprecisely defined or inadequately controlled, for example pelvic adequacy was defined predominantly by clinical assessment and fewer than 10% of women underwent x-ray pelvimetry. Most hospitals in the UK and USA use very strict criteria before undertaking a trial of labour for a breech and maybe only 20% of women would be considered suitable (Hauth and Cunningham,2002) This is a sharp contrast to the 57% who actually delivered vaginally in the planned vaginal birth group Statistical analysis All results were analysed by intention to treat (which I would argue does not give an accurate picture of mode of delivery effects) Fishers exact test and Wilcoxons rank sum test were used Relative risks and a 95% confidence interval were reported for the differences in the major outcomes. The statistical analysis was thorough but I believe the results on which the analysis was carried out were flawed and that the statistics are of no use to us. The question we want to ask is if mode of delivery affects maternal and fetal mortality and morbidity and after study of this trial it is clear it does not answer this question.
The confidential enquiry into stillbirth and deaths in infancy’s 7th annual report focuses on breech presentation. It concludes that the undiagnosed breech is at the greatest risk and recommends an increased effort to diagnose antenatally and in labour including an increased use of ultrasound It states the commonest cause of death for breech babies is hypoxia as clear from post-mortem findings. The single and most avoidable factor was suboptimal care in labour rather than the conduct of the delivery itself. Mechanical difficulties as a sole cause of death was rare. However inexperience at the time of delivery exacerbated the risk to an already hypoxic baby
Conclusions To conclude, as babies are often breech for a reason, such as abnormality, placenta praevia, or any scenario where the head will not fit into the pelvis and cannot engage. Caesarean section will always be essential for the delivery of some breech babies. However, when problems such as this have been ruled out, most breech babies can be born vaginally without incident. Looking at the two key pieces of evidence the term breech trial and the confidential enquiry, in my opinion there is insufficient evidence to recommend a blanket intervention of caesarean section and more onus should be put on detection, External Cephalic Version, moxibustion and excellent care in labour. It remains possible that women will choose to deliver vaginally and that some women for whom a caesarean section is planned will labour too quickly for the operation to be undertaken (nearly 10% of women assigned to deliver by caesarean section in the Term Breech trial delivered vaginally). Thus a good way of conducting a vaginal breech birth still needs to be found. The midwifery model of care has not been researched with regards to breech, and breech is rapidly becoming something UK midwives know very little about. A few independent midwives provide the only service to women in the UK who want a natural breech birth. Mary Cronk independent midwife gave a talk at the Association of Radical Midwives National meeting in June 1998 on the midwifery skills required for a breech birth. I would like to see her ideas researched thoroughly as the midwifery model. She proposes
Currently women have little choice in the births of their breech babies. The choice stands as the heavily recommended caesarean section or the possibility of a badly managed labour and assisted vaginal delivery, which is likely to cause harm to the fetus. Much more research is required with more scope to determine how to safely deliver the vaginal breech and how to give women a choice and a good service.
The Canadian Consensus on Breech Management at Term. http://sogc.medical.org/sogc_docs/public/guidelines/cbree3.htm Retrieved Nov 8, 2002. Collea J, Chein C, Quilligan E (1980) A randomized management of term frank breech presentation: a study of 208 cases. American Journal of Obstetrics and Gynecology 137: 235-44. Confidential enquiry into stillbirths and death in infancy (2000) 7th Annual report London Maternal and child health research consortium Cronk M (1998) Midwifery skills needed for breech birth Midwifery Matters, 78 http://www.radmid.demon.co.uk/Skills.htm Gimovsky M, Wallace R, Schifrin B (1983) Randomised management of the nonfrank breech presentation at term: a preliminary report. American Journal of Obstetrics and Gynecology 146: 34-40. Hannah, M. & Hannah, W. (1996) Caesarean section or vaginal birth for breech presentation at term. British Medical Journal. 312 p1433-1434. http://www.bmj.com//cgi/content/full/312/7044/1433 Retrieved Nov 5, 2002. Hannah, M.A.; Hannah, W.J.; Hewson, S.A.; Hodnett, E.D.; Saigal, S.; Willan, A.R. (2000) Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomized multicentre trial. The Lancet. 356 9239 p 1375-1383. Hauth J and Cunningham F (2002) Vaginal breech delivery is still justified Obstetrics and Gynecology 99, 6 p1113-4 Hofmeyr GJ, Hannah ME (Last updated 2000) Planned caesarean section for term breech delivery (Cochrane Review) The Cochrane Library, Issue 4, 2002. Oxford: Update Software. Page L (2000) Using evidence to inform practice (Chapter 2) In The New Midwifery Science and Sensitivity in Practice (Ed) Page L London Churchill Livingstone Term Breech Trial Newsletter. Vol. 4. Issue 12. December 31, 1998 http://www.utoronto.ca/miru/breech/ Retrieved Nov 7, 2002. Term Breech Trial Newsletter. Vol. 4. Issue 9. September 30,1998 http://www.utoronto.ca/miru/breech/9809news.pdf Retrieved October 24, 2002. Term Breech Trial Newsletter. Vol. 6. Issue 3. March 31, 2000. http://www.utoronto.ca/miru/breech/0003news.pdf Retrieved November 6, 2002. Thornton J and Hayman R (2002) Staff experience in vaginal breech delivery British Journal of Midwifery 10:7 p408-410 |