Cameron 2013.

Methods	Location: Scotland, UK Recruitment time: from March 2009 to March 2011 Sample size calculation and the outcome of focus: Assuming two‐sided alpha of 0.05 and power of 80%, a sample size of 100 participants in each arm was calculated to detect difference between 90% easy insertions with empty bladder and 99% easy insertions with filled bladder.
Participants	General with N: 200 women Source: family planning clinic in Edinburgh, Scotland, UK Inclusion criteria: wished to have an intrauterine method of contraception, routinely attended clinic for counseling about method by clinician, before being given an appointment for subsequent insertion of device, agreed to attend for IUD or IUS insertion with full bladder Exclusion criteria: no other criteria
Interventions	Women drank 1 liter (L) (or 6 glasses) of fluid in hour before appointment. Timing of bladder emptying: 1) Immediate: went to toilet immediately prior to IUC insertion 2) Delayed: went to toilet after IUC insertion
Outcomes	Primary: pain during IUD insertion (10‐point scale where 0 = no pain and 10 = agony) Secondary: ease of insertion (primary for trial)
Notes	IUC used: Mirena, Slimline TT380, Nova T 380, Multiload 375, UT 380 and Mini TT 380
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated sequence in blocks of 10
Allocation concealment (selection bias)	Low risk	Sequentially numbered, opaque, sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	Loss to follow‐up: none