Rock 1969.

Methods	Single‐centre quasi‐randomised controlled trial at Temple University Obstetrical Servlce, Philadelphia, Pennsylvania, USA.
Participants	40 women in labour “Patients were selected from the wards of the Temple University Obstetrical Service, and they were selected by the following criteria: a) the patients were believed to be at term; b) as far as could be ascertained, no obstetrical or other abnormalities existed; c) the patients were believed to be in labour; and d) labour had not progressed beyond 4 cm of cervical dilation".
Interventions	Hypnosis group: hypnosis with suggestions for comfort, relaxation and anaesthesia provided by a medical student who sat by the woman. The medical student also undertook routine medical observations and examinations. Control: a medical student sat by the woman and undertook routine medical observations and examinations (usual care).
Outcomes	Use of pharmacological analgesia, pain intensity, use of epidural/neuroaxial block as additional analgesia, postnatal depressive symptoms.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quasi‐randomised controlled trial ‐ "the patient was assigned, at any hour of the day or night, to either the experimental (hypnotic) or control group if she met the criteria for the study. If the last digit of the hospital history number was odd, the patient was assigned to the experimental group; if the digit was even, the patient was assigned to the control group."
Allocation concealment (selection bias)	High risk	Quasi‐randomised controlled trial with an attempt to conceal allocation "in order to eliminate any bias in assigning patients to either the experimental or the control group, history number was concealed until after the patient had been examined and the decision had been made that she met all the criteria for the study."
Blinding of participants (objective outcomes)	Low risk	"After the patient was assigned to the experimental group, the hypnotist began the procedure by telling her that he would help her with her labour. The patient was not told that she was to be hypnotized; she was not asked if she wished to be helped."
Blinding of participants (subjective outcomes)	Unclear risk	Women not told their group allocation but there was no reporting about whether blinding was successful.
Blinding of personnel (performance bias)	High risk	The hypnosis intervention was provided by main care provider for labour so high risk of bias.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Some outcomes were assessed by the hypnotist, some by a resident and postpartum outcomes were assessed by a co‐author who had not been present in the labour room and who was not previously known to the woman. Unclear if the resident and/or co‐authors were blind to women's group allocation.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intervention was provided during labour and no losses were noted.
Selective reporting (reporting bias)	Unclear risk	Results mainly reported in the narrative and only tabulated for the experimental group. Only reports results for pain as a P value "patients in the experimental group rated their experience as less painful" (P < 0.01).
Other bias	Unclear risk	Baseline characteristics for patients not presented ‐ narrative report on groups being comparable for ages, despite differences in parity ‐ no other detail.