Table 2.

Level of evidence

Variable	Effect(RR/MD/SMD)	95%CI	P	I2(%)	P(X2 test)	Statistical Method	Studies (N)	Sample size (N)	Level of evidence
Pregnancy rate	1.23	1.13, 1.34	< 0.00001	30	0.16	Fixed effects models	11	2909	Very low
Endometrial pattern	1.47	1.27, 1.70	< 0.00001	18	0.30	Fixed effects models	6	552	Moderate
Endometrial thickness	0.41	0.11, 0.72	0.008	72	0.0004	Random effects models	9	666	Low
Electroacupuncture	0.83	0.22, 1.43	0.008	83	0.003	Random effects models	3	298	Low
Acupuncture	0.20	−0.01, 0.40	0.06	0	0.56	Random effects models	6	368	Moderate
Embryo transfer rate	2.04	1.13, 3.70	0.02	0	0.85	Fixed effects models	2	124	Very low
RI	−0.08	− 0.15, − 0.02	0.01	99	< 0.00001	Random effects models	5	437	Very low
With moxibustion	−0.01	− 0.02, − 0.00	0.0006	0	0.90	Random effects models	2	154	Low
Without moxibustion	−0.15	− 0.28, − 0.01	0.03	99	< 0.00001	Random effects models	3	283	Very low
PI	−2.39	−3.85, −0.93	0.001	97	< 0.00001	Random effects models	5	437	Very low
With moxibustion	−0.54	−0.86, − 0.22	0.0010	0	0.60	Random effects models	2	154	Low
Without moxibustion	−3.69	−5.93, −1.45	0.001	97	< 0.00001	Random effects models	3	283	Very low
S/D	−0.60	−0.89, − 0.30	< 0.0001	15	0.28	Fixed effects models	2	187	Low