Summary of findings 3. Combined oral contraceptive pill compared to levonorgestrel‐releasing intrauterine system for heavy menstrual bleeding.

Combined oral contraceptive pill compared to levonorgestrel‐releasing intrauterine system for heavy menstrual bleeding
Patient or population: heavy menstrual bleeding Setting: primary care Intervention: Combined oral contraceptive pill Comparison: levonorgestrel‐releasing intrauterine system
Outcomes	Anticipated absolute effects* (95% CI)		Relative effect (95% CI)	№ of participants (studies)	Certainty of the evidence (GRADE)	Comments
	Risk with levonorgestrel‐releasing intrauterine system	Risk with Combined oral contraceptive pill
Treatment success (PBAC < 100 at end of treatment or no requirement for alternative treatment ) follow up: mean 12 months	868 per 1,000	581 per 1,000 (373 to 760)	OR 0.21 (0.09 to 0.48)	151 (2 RCTs)	⊕⊕⊝⊝ LOW 1	Participants were not blinded
Satisfaction with treatment follow up: mean 12 months	842 per 1,000	607 per 1,000 (242 to 882)	OR 0.29 (0.06 to 1.40)	37 (1 RCT)	⊕⊝⊝⊝ VERY LOW 1 2	Participants were not blinded
Other primary menstrual bleeding outcomes: semi‐objectively assessed menstrual blood loss, subjectively assessed menstrual blood loss						No study reported these outcomes in this comparison
Adverse effects ‐ Any adverse events	850 per 1,000	895 per 1,000 (555 to 983)	OR 1.50 (0.22 to 10.14)	39 (1 RCT)	⊕⊝⊝⊝ VERY LOW 1 2	Individual adverse effects did not differ by group
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio; OR: Odds ratio;
GRADE Working Group grades of evidence High certainty: We are very confident that the true effect lies close to that of the estimate of the effect Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect

^{1 Risk of bias downgraded two levels because lack of blinding may have had a substantial effect on the measurement of this outcome; also it was unclear whether the involvement of the funder might have influenced the findings}

^{2 Precision downgraded level because effects measured in only one trial}