Claman 2004.
| Methods | Single centre, parallel design with random number table. Concealment of allocation: third party No blinding used. Duration of the study and follow up not stated Power calculation: sample size of 190 with a power of 0.8 to detect an increase in pregnancy rate from 15% to 30% between groups with an alpha of 0.05. ITT: no |
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| Participants | 75 women, 189 cycles, > 2 years subfertility Exclusion criteria: cycles with endogenous LH surge Mean age of women: short hCG‐IUI interval: 34.4 yrs ± 3.6 and long hCG‐IUI interval: 34.3 yrs ± 3.6 Type of subfertility: unexplained, endometriosis stage 1 or 2, male factor (WHO 1992), clomiphene resistant oligo‐ovulation, or combination of factors |
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| Interventions | Stimulation method: 100 to 225 IU FSH, 5000 IU hCG im or 10,000 IU hCG sc IUI either 32 to 34 hours or 38 to 40 hours after injection of hCG Type of semen not explicitly stated. Semen prepared with a two‐layer density gradient separation technique, final sample suspended in 0.35 ml of culture medium Insemination procedure: Tomcat catheter high up in the uterine fundus, one insemination per cycle |
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| Outcomes | Pregnancy rate per cycle: short interval 20/96 (20%), long interval group 14/93 (15%) Secondary outcomes not stated Pregnancy diagnosed: transvaginal ultrasound demonstrating heart activity |
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| Notes | Inclusion of couples with oligo‐ovulation Setting: Division of Reproductive Medicine, Department of Obstetrics and Gynecology, The Ottawa Hospital, Canada No funding |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | None stated; the author comment ‘next random number in the table’ does not state the random sequence generation |
| Allocation concealment (selection bias) | Low risk | Third party (a nurse) in the clinical care team picked the next random number in the table and crossed it |
| Blinding of participants and personnel (performance bias) All outcomes | Low risk | No blinding, but outcome not likely to be influenced |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | No blinding, but outcome not likely to be influenced |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | Incomplete outcome data addressed adequately |
| Selective reporting (reporting bias) | Unclear risk | No protocol available |
| Other bias | Low risk | No other bias |