Ref (type)	Population	Outcome, Interventions	Results and statistical analysis	Effect size	Favours
Mean menstrual blood loss
Systematic review	44 women Data from 1 RCT	Median reduction in menstrual blood loss 104 mL with progestogen-releasing IUD 94 mL with oral norethisterone	P = 0.56		Not significant
Systematic review 4-armed trial	30 women	Menstrual blood loss with progestogen-releasing IUD (65 micrograms/day) with long-cycle oral progestogen (norethisterone) Absolute results not reported	Between-group differences not assessed
Systematic review	44 women Data from 1 RCT	Proportion of women who were amenorrhoeic 3 months 32% with progestogen-releasing IUD 0% with norethisterone Absolute numbers not reported	Reported as significant P value not reported	Effect size not calculated	norethisterone