Comparison 17. Levonorgestrel split dose, 24 hours versus 12 hours.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Observed number of pregnancy (all women)	1	2060	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.53, 1.82]
2 Observed number of pregnancies (by risk status)	1	2012	Risk Ratio (M‐H, Fixed, 95% CI)	0.98 [0.53, 1.81]
2.1 High‐risk women	1	446	Risk Ratio (M‐H, Fixed, 95% CI)	0.39 [0.13, 1.23]
2.2 Low‐risk women	1	1566	Risk Ratio (M‐H, Fixed, 95% CI)	1.56 [0.71, 3.42]
3 Specific side effects	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
3.1 Nausea	1	2071	Risk Ratio (M‐H, Fixed, 95% CI)	0.96 [0.72, 1.29]
3.2 Vomiting	1	2071	Risk Ratio (M‐H, Fixed, 95% CI)	0.83 [0.37, 1.85]
3.3 Headache	1	2071	Risk Ratio (M‐H, Fixed, 95% CI)	0.89 [0.58, 1.36]
3.4 Dizziness	1	2071	Risk Ratio (M‐H, Fixed, 95% CI)	1.23 [0.86, 1.74]
3.5 Breast tenderness	1	2071	Risk Ratio (M‐H, Fixed, 95% CI)	0.60 [0.40, 0.91]
3.6 Lower abdominal pain	1	2071	Risk Ratio (M‐H, Fixed, 95% CI)	0.76 [0.53, 1.08]
4 Menses	1		Risk Ratio (M‐H, Fixed, 95% CI)	Subtotals only
4.1 Delay	1	1978	Risk Ratio (M‐H, Fixed, 95% CI)	0.79 [0.53, 1.17]