Table 3. Sensitivity analysis and publication bias results.

Risk Factor	Fixed pooling model		Random pooling model		egger’s test P-value
	OR (95%CI)	P-value	OR (95%)	P-value
EMT on HCG day	1.337 (1.281–1.395)	<0.001	1.951 (1.598–2.381)	<0.001	<0.001
History of EP	1.291 (1.184–1.409)	<0.001	1.541 (1.213–1.957)	<0.001	0.127
Infertility type	1.326 (1.171–1.502)	<0.001	1.566 (1.224–2.004)	<0.001	-
EMT at transplantation	1.345 (1.189–1.521)	<0.001	1.511 (1.197–1.908)	0.001
Previous miscarriage	2.054 (1.310–3.222)	0.002	2.054 (1.310–3.222)	0.002
PCOS	2.164 (1.386–3.381)	0.001	2.164 (1.386–3.381)	0.001
Male factor infertility	0.508 (0.387–0.668)	<0.001	0.534 (0.342–0.834)	0.006
DOR	1.751 (1.346–2.279)	<0.001	1.751 (1.346–2.279)	<0.001
Tubal factor infertility	1.724 (1.596–1.862)	<0.001	1.851 (1.609–2.130)	<0.001	0.060
Embryo transfer stage	1.892 (1.695–2.112)	<0.001	1.870 (1.417–2.466)	<0.001	0.843
Type of transfer	1.422 (1.283–1.576)	<0.001	1.463 (1.062–2.016)	0.02
Endometrial preparation	2.067 (1.718–2.487)	<0.001	2.067 (1.718–2.487)	<0.001
E2 level on HCG day	1.001 (1.001–1.001)	<0.001	1.001 (1.000–1.002)	<0.001
Previous tubal surgery	2.692 (2.075–3.494)	<0.001	2.692 (2.075–3.494)	<0.001
Maternal age	0.973 (0.956–0.990)	0.002	0.935 (0.880–0.993)	0.029
No. of transferred embryos	1.364 (1.219–1.526)	<0.001	1.517 (1.226–1.878)	<0.001	0.063
Previous of cesarean section	1.632 (1.005–2.652)	0.048	1.621 (0.976–2.692)	0.062
Previous pregnancy	1.227 (1.057–1.423)	0.007	1.205 (1.008–1.442)	0.041
History of pelvic surgery	1.447 (1.277–1.640)	<0.001	1.909 (1.349–2.701)	<0.001

EMT:endometrial thickness; HCG:human chorionic gonadotropin; EP:ectopic pregnancy; PCOS:polycystic ovarian syndrome; DOR:diminished ovarian reserve; E2:estradiol.