Five studies to critique with midwifery students

3217004434_e547fa3da5No less than four of my lecturer colleagues have hinted to me (and I use that term loosely … some hinted quite strongly, and one mentioned chocolate) over the past couple of weeks that it would be really helpful if I wrote a blog post which identified some studies that they could critique with midwifery students in upcoming research modules.

Happily, I rather liked the sound of this challenge, so here are five recent(ish) papers relating to the care of women during labour that I reckon would make for juicy discussions … and even if you’re not teaching research this semester, you might find them interesting to ponder.

I’ve even added some helpful notes and questions about each…

1. Self-hypnosis for intrapartum pain management in pregnant nulliparous women: a randomised controlled trial of clinical effectiveness.

  • This is the largest UK trial on this topic to date and it is an RCT whose basic design will be understandable for even beginning research students.
  • The results don’t show that self-hypnosis makes a difference in terms of epidural use, although its impact on the women’s levels of postnatal anxiety and fear about childbirth was significant.
  • Readers will need to look closely at the nature (and definition) of the intervention and at the methods used and think through the experiences of the women in each group in order to decide whether they feel that the results cast real doubt on self-hypnosis.
  • The researchers themselves point out some key limitations.  Might a differently designed trial have led to different results?
  • Taking everything you learned from this into account, and if you didn’t have to live in the real world where (lack of) funding is a major constraint on research, how would you design a future RCT on this topic?
Objective: (Primary) To establish the effect of antenatal group self-hypnosis for nulliparous women on intra-partum epidural use.
Design: Multi-method randomised control trial (RCT).
Setting: Three NHS Trusts.
Population: Nulliparous women not planning elective caesarean, without medication for hypertension and without psychological illness.
Methods: Randomisation at 28–32 weeks’ gestation to usual care, or to usual care plus brief self-hypnosis training (two × 90-minute groups at around 32 and 35 weeks’ gestation; daily audio self-hypnosis CD). Follow up at 2 and 6 weeks postnatal.
Main outcome measures: Primary: epidural analgesia. Secondary: associated clinical and psychological outcomes; cost analysis.
Results: Six hundred and eighty women were randomised. There was no statistically significant difference in epidural use: 27.9% (intervention), 30.3% (control), odds ratio (OR) 0.89 [95% confidence interval (CI): 0.64–1.24], or in 27 of 29 pre-specified secondary clinical and psychological outcomes. Women in the intervention group had lower actual than anticipated levels of fear and anxiety between baseline and 2 weeks post natal (anxiety: OR −0.72, 95% CI −1.16 to −0.28, P = 0.001); fear (OR −0.62, 95% CI −1.08 to −0.16, P = 0.009). Postnatal response rates were 67% overall at 2 weeks. The additional cost in the intervention arm per woman was £4.83 (CI −£257.93 to £267.59).
Conclusions: Allocation to two-third-trimester group self-hypnosis training sessions did not significantly reduce intra-partum epidural analgesia use or a range of other clinical and psychological variables. The impact of women’s anxiety and fear about childbirth needs further investigation.
Downe S, Finlayson K, Melvin C et al (2015). Self-hypnosis for intrapartum pain management in pregnant nulliparous women: a randomised controlled trial of clinical effectiveness. BJOG: An International Journal of Obstetrics and Gynaecology. Online ahead of print.


2. Nulliparous Women in the Second Stage of Labor: Changes in Delivery Outcomes Between Two Cohorts From 2000 and 2011

  • A lot of the data that we see these days is derived from retrospective cohort studies such as this one, and the topic and nature of this study means that you don’t have to have spent years in practice to be able to understand and think about the issues that are under discussion here.
  • The results show some of the changes that occurred in the outcomes of two different cohorts of women.  Are there other relevant factors – perhaps including changes in wider culture – which might have affected the outcomes?  Can you think of factors that might affect the length of second stage?  Why is it important to think about such things when analysing a paper like this?
  • Readers will need to think carefully about how data is collected, how care and outcomes are recorded and think about issues such as confounding factors.
OBJECTIVE: To evaluate changes over the past decade in the mode of delivery and second-stage duration in nulliparous women.
METHODS: We conducted a retrospective cohort study at a single institution of nulliparous women reaching complete cervical dilation with singleton gestations 36 weeks or greater from January 1, 2011, to December 31, 2012, and compared these with a prior cohort prospectively collected from July 28, 2000, to February 28, 2003. We excluded pregnancies with prenatally diagnosed fetal anomalies. The primary outcome was cesarean delivery. Secondary outcomes included second-stage duration, rates of operative vaginal delivery (forceps and vacuum collectively), and indications for cesarean delivery and operative vaginal delivery.
RESULTS: There were 1,023 mother-neonate pairs in the prior cohort and 1,476 in the current cohort. In the prior and current cohorts, respectively, 2% compared with 6% underwent cesarean delivery, 21% compared with 10% underwent operative vaginal delivery, and 77% compared with 84% had spontaneous vaginal delivery (all P<.01). Compared with the prior cohort, the adjusted odds (OR) of cesarean delivery (compared with any vaginal birth) for current patients was 1.74 (95% confidence interval [CI] 1.04-2.91), and in a separate regression model, the adjusted OR of operative vaginal delivery (compared with spontaneous vaginal delivery or cesarean delivery) was 0.42 (95% CI 0.33-0.54). Median (25th, 75th percentile) second-stage duration significantly increased from 38 (20, 71) to 42 (22, 87) minutes (P<.01), but this difference was nullified after adjusting for confounders.
CONCLUSION: Comparing cohorts from 2000 and 2011, although the second-stage duration has not changed appreciably, nulliparous women in the second stage of labor at our institution are twice as likely to undergo cesarean delivery and half as likely to undergo operative vaginal delivery.
Fitzwater, JL, Owen, J, Ankumah, N-A et al (2015).  Nulliparous Women in the Second Stage of Labor: Changes in Delivery Outcomes Between Two Cohorts From 2000 and 2011. Obstetrics & Gynecology: doi: 10.1097/AOG.0000000000000872


Reviews of perineal support during birth

The final three studies are on the same topic; the important and topical question of the best approach (or package of care) as far as protecting women’s perineums in labour is concerned.  Although this is sometimes termed the ‘hands on or hands poised’ debate, it is far more complex than this, and I think is can be incredibly useful to look at different systematic reviews (or other kinds of reviews, come to that) on the same topic by different groups of researchers.  Apart from anything else, it can be a really effective demonstration of how much the conclusions of a study can be affected by the pre-existing stance and beliefs of the researcher.  I have talked more about that in this article.

Questions to ask of all three of these reviews include:

  • How did the researchers select the studies for inclusion?  Have they all chosen the same studies?  If not, why do you think this might be?  Could any differences in the number and nature of the included studies have made a difference to the results and/or the conclusions that they have drawn?  If so, or if not, how and why do you think this?
  • Does the language, tone or approach taken within each article tell you anything about the researchers’ pre-existing standpoint?  Do you think this has affected the conclusions that were reached?  Do you think you would have reached the same conclusions?  Why, or why not?
  • The interventions that are under discussion here are not single and easily measured.  Some may be better described as ‘packages of care’.  How does that affect our ability to research them?
  • Do the results of these reviews make you think that one or other approach is better?  Why is that?


3. Manual perineal support at the time of childbirth: a systematic review and meta-analysis.

BACKGROUND: Genital tract trauma is common with vaginal births and is associated with significant morbidity, particularly with obstetric anal sphincter injuries (OASIS). Debate continues regarding the effectiveness of perineal support during childbirth in reducing the risk of trauma.
OBJECTIVES: This review aimed to assess the effect of routine ‘hands on’/manual perineal support (MPS) during childbirth, versus ad hoc/no perineal support (‘hands off/poised’), on the risk and degree of perineal trauma.
SEARCH STRATEGY: This review is registered on PROSPERO ( We searched the CENTRAL, Embase, Medline, CINAHL, and OVIDs midwifery and infant care databases (from inception to December 2014).
SELECTION CRITERIA: Published randomised controlled trials (RCTs) and non-randomised studies (NRSs) evaluating any ‘hands on’ perineal support technique during childbirth.
DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trials for inclusion, data extraction, and methodological quality. Discrepancies were resolved by discussion with a third reviewer.
MAIN RESULTS: We included five RCTs and seven NRSs in the review. Meta-analysis of RCTs did not demonstrate a statistically significant protective effect of MPS on the risk of OASIS (three studies, 6647 women; relative risk, RR 1.03; 95% confidence interval, 95% CI 0.32-3.36; statistical test for heterogeneity I2  = 71%). Meta-analysis of NRSs showed a significant reduction in the risk of OASIS with MPS (three studies, 74 744 women; RR 0.45; 95% CI 0.40-0.50; I2  = 32%).
CONCLUSION: Current evidence is insufficient to drive change in practice. An adequately powered randomised trial with an efficient design to evaluate the complex interventions adopted as part of MPS policies, ensuring controlled childbirth, is urgently needed.
Bulchandani S, Watts E, Sucharitha A et al (2015).  Manual perineal support at the time of childbirth: a systematic review and meta-analysis.  BJOG.  doi: 10.1111/1471-0528.13431. [Epub ahead of print]


4. The future technique for perineal management of second stage of labour? A modified systematic literature review.

BACKGROUND: vaginal birth is often accompanied with perineal trauma that affects postpartum morbidity. There are many techniques for protecting the perineum from injury during childbirth. The Hands-On or Hands Poised (HOOP) study (McCandlish et al., 1998) was the first trial that compared different techniques of perineal protection during the second stage of labour with very little research subsequently being undertaken.
OBJECTIVES: to systematically review all available literature that compares the hands-on and hands-poised techniques of perineal management during the second stage of labour.
METHODS: using the principles of a modified systematic literature review, quantitative, comparative and primary research studies were selected. These were assessed for quality using the Critical Appraisal Skills Programme (CASP) framework including a data extraction form. The results were reported narratively.
MAIN RESULTS: five studies were included and outlined the importance of both techniques. The hands-poised technique appeared to cause less perineal trauma and reduced rates of episiotomy. The hands-on technique resulted in increased perineal pain after birth and higher rates of postpartum haemorrhage.
CONCLUSION: as the five studies selected for this review have widely differing variables, comparisons that have been drawn must be viewed with caution. Evidence would suggest that the hands-poised technique is a safe and recommended technique for perineal management and discussions of such a technique should be included in all midwifery education and training programmes. The challenge for midwives is how to support women in making informed choices about perineal management during childbirth. Until there is conclusive evidence, the choice of the hands-on or hands-poised technique will ultimately be determined by the clinical judgment of the individual midwife at the time of birth. Further research is recommended. Thorough conclusions could significantly impact on reducing postpartum morbidity and improving women’s sexual health and well-being in the long term, throughout the world.
Petrocnik P, Marshall JE (2015). Hands-poised technique: The future technique for perineal management of second stage of labour? A modified systematic literature review. Midwifery. 31(2):274-9. doi: 10.1016/j.midw.2014.10.004.


5. The effect of “hands on” techniques on obstetric perineal laceration: A structured review of the literature.

OBJECTIVE: The purpose of this structured review was to review current evidence of “hands on” and “hands off” techniques as it relates to rates of perineal laceration in order to provide direction for future research in this important area of midwifery practice.
METHOD: A structured literature search using all identified keywords and index terms was undertaken in MEDLINE, EMBASE Joanna Briggs Institute, CINAHL, TRIP, and OVID nursing database.
FINDINGS: A total of 24 papers were identified from the initial searches as potentially relevant to the review questions. Of these a total of nine papers were considered relevant for this review. These nine included one systematic review with meta-analysis, four randomised controlled trials (RCTs), one quasi-experimental study and three cohort studies.
CONCLUSION: “Hands on” techniques have been traditionally used but not been well defined in the literature, therefore it is currently unclear as to whether or not “hands on” technique can reduce perineal laceration. More studies are required to test the effectiveness of a standardised “hands on” technique and also to determine what part other factors such as maternal position, visualisation and use of water might play in perineal laceration rates.
Wang H, Jayasekara R, Warland J (2015).  The effect of “hands on” techniques on obstetric perineal laceration: A structured review of the literature. Women and Birth. pii: S1871-5192(15)00035-9. doi: 10.1016/j.wombi.2015.02.006. [Epub ahead of print]


Happy critiquing!


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