Muzii 2000.

Methods	Location: University departments, Rome, Italy No. of centres: 2 Recruitment period: January 1994 to June 1997
Participants	Inclusion criteria: 20‐35 yrs, moderate to severe dysmenorrhoea and/or chronic pelvic pain, not desiring fertility Exclusion criteria: treatment for endometriosis in previous 6 months No. randomised: 70 No. analysed: 68
Interventions	Post‐surgical medical therapy Gr A (n=35): cyclic monophasic oral contraceptive pill (ethinyl estradiol 0.03 mg, gestodene 0.075 mg) for 21 days with 7 pill free days x 6/12 Gr B (n=35): no treatment
Outcomes	Recurrence of pain and time to recurrence Recurrence of cysts
Notes	Power calculation: yes Funding: NS. Drugs supplied by Population Council
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"randomly allocated to one of two management arms on the basis of a computer generated sequence"
Allocation concealment (selection bias)	Unclear risk	not described
Blinding (performance bias and detection bias) All outcomes	High risk	not mentioned, no placebo
Incomplete outcome data (attrition bias) All outcomes	Low risk	two post‐randomisation withdrawals. Unlikely to have introduced a bias
Selective reporting (reporting bias)	Low risk	important outcomes reported ‐ recurrence of endometriosis, pain, AFS scores. Patients not desiring pregnancy
Other bias	Unclear risk	no information of the baseline characteristics of the groups reported