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. 2018 May 16;2018(5):CD000111. doi: 10.1002/14651858.CD000111.pub4

Rush 1996.

Methods Randomisation by consecutively numbered, computer‐generated random allocation in sealed opaque envelopes.
 Methodological qualities:

  1. selection bias: low risk; adequate concealment at time of randomisation;

  2. performance bias: high risk of bias could have been introduced because researcher could not be blind to group allocation after randomisation;

  3. exclusion bias: high risk of bias;

  4. bias conclusion: high risk of bias. Where 1 or more criteria are not met may cause plausible bias that seriously weakens confidence in the results.
Participants Academic hospital, Ontario, Canada.
 Inclusion criteria:

  1. term pregnancy defined as gestation greater than 37 weeks;

  2. previous CS included (VBAC);

  3. in active labour defined as a cervical dilatation of 3 cm or more;

  4. ruptured membranes on entry also eligible;

  5. ambulation, analgesics and anaesthesia were allowed.


800 women were randomised, 15 were withdrawn 8 from study group and 7 from control group. Nearly half (46%) of the women in the study group did NOT use the bath but were still considered experimental participants with the ITT. 41 of the women did not meet eligibility criteria but were still included and results were analysed.
 Study group: n = 393‐ stated but Experimental group adds up to 394. Control group: n = 392
Interventions Immersion in water during first stage of labour.
The use of a Parker whirlpool hot tub with jets during labour. Bath temperature between 38‐39 degrees celsius. Mean total time in tub was 54 minutes. No births in tub.
No water immersion during labour.
Refer to care being provided by assigned nurse, and all had be trained to care for women using immersion, but not clear if this is 1‐to‐1 second care.
First stage only.
Outcomes Maternal outcomes:

  1. *use of analgesia/anaesthesia;

  2. *augmentation of labour;

  3. *presence of meconium‐stained liquor;

  4. *duration of labour and birth;

  5. *mode of delivery.


Additional outcomes:

  1. maternal age;

  2. gravida;

  3. cervical dilatation;

  4. duration in tub;

  5. VBAC.
Notes Data table 1 incorrect. No response from authors
Dates of trial: February‐September 1998
Funding: not reported
Declaration of interest: not reported
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Computer‐generated
Allocation concealment (selection bias) Low risk Consecutively numbered sealed opaque envelopes
Blinding of participants and personnel (performance bias) 
 All outcomes High risk High risk of bias could have been introduced because women, carers and researcher could not be blind to group allocation after randomisation due to the nature of the intervention
Blinding of outcome assessment (detection bias) 
 All outcomes Unclear risk No information provided
Incomplete outcome data (attrition bias) 
 All outcomes High risk All participants are accounted for, and 15 withdraws were detailed, as were 41 who did not meet criteria but were recruited
Selective reporting (reporting bias) Low risk All outcomes mentioned in methods are reported, and seem appropriate for the study and topic
Other bias Unclear risk No information on this