Chor 2012.

Methods	Location: Chicago, IL, USA Recruitment time: from April 2007 to January 2010 Sample size calculation and the outcome of focus: Based on published literature, and assuming a SD of 23 mm, an alpha of 0.05 and power of 80%, a sample size of 37 participants in each group was calculated to detect a difference of 1.5 cm in the VAS assessment of pain at the time of IUD insertion.
Participants	General with N: 87 women enrolled; 81 received IUDs Source: University of Illinois Medical Center Inclusion criteria: 18 years or older, desiring LNG‐IUS for contraception, without contraindications to using LNG‐IUS, without medical contraindications to NSAIDs, able to provide phone number for follow‐up questions, and had not taken pain medications on day of enrollment Exclusion criteria: not reported
Interventions	1) Ibuprofen 800 mg 2) Placebo containing lactose Timing: 45 min prior to IUD insertion
Outcomes	Primary: Pain at time of tenaculum placement, pain at time of IUD insertion (10 cm VAS; 0 = no pain and 10 = unbearable) Secondary: provider's ease of insertion
Notes	IUC used: LNG‐IUS
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated, source not specified
Allocation concealment (selection bias)	Low risk	Both placebo and ibuprofen were identical in appearance, and were packaged in serially‐numbered envelopes and used in order.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participants, providers and study recruiters were blinded to medication.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Loss to follow‐up: none