Comparison 1. Live birth: assisted hatching compared with no assisted hatching.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1.1 Live birth per woman randomised	14	2849	Odds Ratio (M‐H, Fixed, 95% CI)	1.09 [0.92, 1.29]
1.2 First or repeat attempt	4		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.2.1 First attempt at IVF or ICSI	3	380	Odds Ratio (M‐H, Fixed, 95% CI)	0.78 [0.48, 1.28]
1.2.2 Repeat attempt at IVF or ICSI	1	150	Odds Ratio (M‐H, Fixed, 95% CI)	1.40 [0.62, 3.13]
1.3 Conception mode	6		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.3.1 ICSI only	3	640	Odds Ratio (M‐H, Fixed, 95% CI)	1.54 [1.02, 2.33]
1.3.2 IVF only	3	241	Odds Ratio (M‐H, Fixed, 95% CI)	1.00 [0.60, 1.68]
1.4 Hatching method	14		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.4.1 Chemical	4	366	Odds Ratio (M‐H, Fixed, 95% CI)	1.13 [0.74, 1.74]
1.4.2 Laser	10	2473	Odds Ratio (M‐H, Fixed, 95% CI)	1.07 [0.89, 1.28]
1.5 Prognosis	9		Odds Ratio (M‐H, Fixed, 95% CI)	Subtotals only
1.5.1 Poor prognosis	4	576	Odds Ratio (M‐H, Fixed, 95% CI)	1.46 [0.99, 2.15]
1.5.2 Good prognosis	6	1495	Odds Ratio (M‐H, Fixed, 95% CI)	1.03 [0.83, 1.28]
1.6 Live birth rate by extent of assisted hatching	14	2849	Odds Ratio (M‐H, Fixed, 95% CI)	1.09 [0.92, 1.29]
1.6.1 Thinning only	6	1742	Odds Ratio (M‐H, Fixed, 95% CI)	1.06 [0.86, 1.30]
1.6.2 Breach by hole only	8	1107	Odds Ratio (M‐H, Fixed, 95% CI)	1.15 [0.87, 1.51]
1.7 Fresh or frozen embryo transfer	12	1731	Odds Ratio (M‐H, Fixed, 95% CI)	1.14 [0.92, 1.41]
1.7.1 Fresh	11	1669	Odds Ratio (M‐H, Fixed, 95% CI)	1.16 [0.94, 1.44]
1.7.2 Frozen	1	62	Odds Ratio (M‐H, Fixed, 95% CI)	0.67 [0.22, 2.07]