Werner 2013.
| Methods | The trial was "randomised, controlled, single‐blinded" and "used a three‐arm group design consisting of an intervention group, an active comparison group, and a control group receiving ordinary antenatal care". | |
| Participants | A total of 1222 women were randomised. "... no chronic diseases, uncomplicated pregnancy, nulliparous, older than 18 years, and able to understand and speak Danish." | |
| Interventions | Intervention: "The hypnosis group attended three 1‐hour classes on self‐ hypnosis for childbirth held over three consecutive weeks. A test for hypnotic susceptibility was conducted during the first session... The programme included three audiorecordings including a 20‐minute section especially meant for labour". Total number randomised: n = 497. "The active comparison group (named ‘the relaxation group’...) also attended three antenatal classes, each lasting 1 hour. The programme was taught by the same midwives as in the intervention group and included a variety of body awareness, relaxation and mindfulness techniques. This course also included audiorecordings for homework and labour." Total number randomised: n = 495. "The usual care group received only ordinary antenatal care, which included a nuchal translucency scan at about 12 weeks of gestation, an anomaly scan at about 19 weeks of gestation, four to five visits at the midwifery clinics, and a tour of the birth department." Total number randomised: n = 230. |
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| Outcomes | "The primary endpoint was the use of epidural analgesia during birth. Self‐reported pain was examined as a secondary outcome." Onset of birth (preterm birth; PROM or PPROM) Duration of childbirth
Mode of delivery
Intervention
Child
Postpartum outcomes
"Baseline information and data on self‐reported pain were collected by questionnaire. The first questionnaire was completed at recruitment and included among others: The Ten‐item Perceived Stress Scale, the World Health Organization (WHO)‐5 Wellbeing questionnaire and the following questions about expectancy for labour and labour pain on an 11‐point Likert scale: How do you expect you will experience the pain intensity during labour? To what extent do you expect the labour pain will influence your birth experience in a negative way? To what extent do you expect the labour pain will influence your birth experience in a positive way? How do you expect you will experience the childbirth in general? (Five‐point Likert scale) Six weeks postpartum, the women completed a second questionnaire that included information about their pain experience during labour and delivery. The participants only completed the specific questions about the pain experience if it was relevant. On 11‐point Likert scales (scores: 0–10), they rated the level of perceived pain intensity at the end of the first stage of labour, during the second stage of labour, and just before receiving epidural analgesia, if relevant. They were also asked to what extent their labour pain influenced their birth experience positively and negatively, their perceived level of calmness, and whether they had experienced sufficient pain relief during birth. The Wijmas Delivery Expectancy/Experience Questionnaire, version A (W‐DEQ A) and version B (W‐DEQ B) were used to assess the childbirth experience. This instrument is a well‐validated tool. W‐DEQ A measures fear, confidence, and expectations concerning the upcoming childbirth and W‐DEQ B evaluates the same aspects of the actual childbirth experience." |
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| Notes | The author was contacted in May 2015 and provided additional data including a copy of her PhD dissertation on the trial. | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | "The participants were randomly allocated to either an intervention group (n = 497), an active comparison group (n = 495), or a control group (n = 230) using a computer‐generated interactive voice‐response telephone randomisation system. The randomisation programme used the participant’s unique personal identification number, which ensured that the participant could only be randomised once." |
| Allocation concealment (selection bias) | Low risk | "The participants were randomly allocated to either an intervention group (n = 497), an active comparison group (n = 495), or a control group (n = 230) using a computer‐generated interactive voice‐response telephone randomisation system. The randomisation programme used the participant’s unique personal identification number, which ensured that the participant could only be randomised once." Comment: presumably the use of an Interactive Voice Response Randomization System meant that assignment could not be foreseen. |
| Blinding of participants (objective outcomes) | Low risk | No blinding, but, lack of blinding unlikely to effect objective measures. |
| Blinding of participants (subjective outcomes) | High risk | No blinding. |
| Blinding of personnel (performance bias) | Unclear risk | "The midwives assisting the birth were blinded to the allocated treatment as the participants were told not to inform the staff about their type of training. The effectiveness of this blinding was investigated by asking the midwife to estimate the woman’s allocate treatment immediately after the delivery. We received 699 (59.8%) forms from the midwives on their estimation of the women’s allocated treatment." "The accuracy of the midwives estimation was highest in the relaxation group (58.4%) and lowest in the hypnosis group (31.5%)." |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | "Information about the participant’s allocated treatment was removed from the data set, so that data management could be performed without knowledge of the participant’s allocated treatment." |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 4 excluded from hypnosis group and 1 excluded from relaxation group after randomisation due to not meeting inclusion criteria. "Information was available for all participants with respect to baseline characteristics and the primary outcome: use of epidural analgesia. The overall response rate for the questionnaire 6 weeks postpartum was high (97.0% in the control group and 98.4% in the two intervention groups)." |
| Selective reporting (reporting bias) | Low risk | A few outcomes specified in the protocol have not been reported in any of the 3 reports of the trial or the PhD dissertation: infection during birth and 6 weeks postpartum (mother and child); child’s condition and well‐being at 6 months follow‐up. Comment: a request for further information was sent to the first author who provided additional data, including the PhD dissertation. The 2 missing outcomes are a very small proportion of the many reported for the trial and were not considered to put the trial at significant risk of reporting bias. |
| Other bias | Low risk | Baseline characteristics similar between the 3 groups, apart for education – where control group had fewer women who had no higher education – 17 (3.5% hypnosis group compared to 10, 2.0 % in relaxation group compared to only 2, 0.9% in care as usual group) – reported in 2 reports. |
DSM‐IV: Diagnostic and Statistical Manual of Mental Disorders 4th edition EPDS: Edinburgh Postnatal Depression Scale HDU: high dependency unit ICU: intensive care unit IPT: ischaemic pain task MMPI: Minnesota Multiphasic Personality Inventory NICU: neonatal intensive care unit PPH: postpartum haemorrhage PPROM: preterm premature rupture of membranes PROM: premature rupture of membranes SCBU: special care baby unit