Comparison 6. 20 ug ethinyl estradiol and 100 ug levonorgestrel, 28‐day versus 336‐day cycles for one year.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
6.1 Overall discontinuation	1	79	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.52 [0.19, 1.45]
6.2 Discontinuation for bleeding reasons	1	79	Peto Odds Ratio (Peto, Fixed, 95% CI)	1.57 [0.26, 9.47]
6.3 Pregnancy	1	79	Peto Odds Ratio (Peto, Fixed, 95% CI)	Not estimable
6.4 Mean of total bleeding days (bleeding + spotting) in first trimester (84 days)	1	73	Mean Difference (IV, Fixed, 95% CI)	0.70 [‐4.22, 5.62]
6.5 Mean of total bleeding days (bleeding + spotting) in second trimester (84 days)	1	64	Mean Difference (IV, Fixed, 95% CI)	1.40 [‐5.55, 8.35]
6.6 Mean of total bleeding days (bleeding + spotting) in third trimester (84 days)	1	61	Mean Difference (IV, Fixed, 95% CI)	‐3.80 [‐10.59, 2.99]
6.7 Mean of total bleeding days (bleeding + spotting) in fourth trimester (84 days)	1	60	Mean Difference (IV, Fixed, 95% CI)	‐3.20 [‐10.48, 4.08]
6.8 Mean spotting days in first trimester	1	73	Mean Difference (IV, Fixed, 95% CI)	4.50 [1.00, 8.00]
6.9 Mean spotting days in second trimester	1	64	Mean Difference (IV, Fixed, 95% CI)	6.90 [1.43, 12.37]
6.10 Mean spotting days in third trimester	1	61	Mean Difference (IV, Fixed, 95% CI)	2.60 [‐2.04, 7.24]
6.11 Mean spotting days in fourth trimester	1	60	Mean Difference (IV, Fixed, 95% CI)	5.60 [‐0.94, 12.14]
6.12 Mean bleeding days in first trimester	1	73	Mean Difference (IV, Fixed, 95% CI)	‐3.80 [‐7.29, ‐0.31]
6.13 Mean bleeding days in second trimester	1	64	Mean Difference (IV, Fixed, 95% CI)	‐5.40 [‐8.87, ‐1.93]
6.14 Mean bleeding days in third trimester	1	61	Mean Difference (IV, Fixed, 95% CI)	‐6.30 [‐10.15, ‐2.45]
6.15 Mean bleeding days in fourth trimester	1	60	Mean Difference (IV, Fixed, 95% CI)	‐8.80 [‐11.01, ‐6.59]
6.16 Symptoms: headache	1	79	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.18 [0.05, 0.72]
6.17 Symptoms: mood changes	1	79	Peto Odds Ratio (Peto, Fixed, 95% CI)	0.13 [0.01, 1.30]