Table 1.

Characteristics of patients in the ART and in the spontaneous conception groups

	ART	Percent	Spontaneous	Percent	p
Pregnancies	2414		582
Female age	34.5 ± 3.8		34.7 ± 3.7		0.208
Male age	37.7 ± 5.0		37.2 ± 4.6		0.028
Female basal FSH (mU/ml)	7.2 ± 2.7		7.4 ± 2.9		0.114
BMI	21.9 ± 3.4		22.7 ± 2.3		<0.001
Primary infertility	1823	75.5	201	34.5	<0.001
Years of infertility	3.5 ± 2.3		3.0 ± 1.9		<0.001
Tubal diseases	514	21.3	20	3.4	<0.001
Endometriosis	160	6.6	12	2.1	<0.001
Reduced ovarian reserve	7	0.3	1	0.2	0.338
Irregular ovulation	32	1.3	32	5.5	<0.001
Unexplained	195	8.1	331	56.9	<0.001
Male factor	733	30.4	158	27.1	0.051
Severe male factor	757	31.4	0	0	<0.001
Mixed male and female factor	16	0.7	28	4.8	<0.001