Table 1.

Demographic Characteristics of the Infertile and Fertile Groups

		Infertile			Fertile
		Treatment	Diagnosis	Testing
	N	7,113	11,548	997	525,695
Maternal Age At Delivery (years)	Mean (SD)	35.3 (4.5)	33.0 (4.8)	33.2 (4.6)	31.2 (4.9)
	% 20–24	0.7	3.6	3.1	8.7
	25–29	9.5	20.8	18.2	28.6
	30–34	32.8	37.5	39.8	37.9
	35–39	38.6	28.6	30.3	20.1
	40–44	16.7	8.7	8.2	4.4
	≥45	1.6	0.8	**	0.4
Follow-up (years) from delivery to last database enrollment date	Mean (SD)	3.3 (3.1)	2.9 (2.9)	2.5 (2.7)	2.9 (2.9)
	% < 1 year	30.2	33.7	40	33.9
	1–2 years	17.1	18.7	18.9	18.3
	2–3 years	11.4	11.8	10.3	12.1
	3–4 years	8.7	8.7	8	8.8
	> 4 years	32.6	27.1	22.8	26.9
Nulliparous	%	50.2	45.4	49.3	42.2
Prepregnancy	Obesity %	9.9	12.4	9.9	8.8
	Smoker %	3.9	5.7	5.4	6.1
	Diabetes %	6.1	5.9	3.7	3.3
Chronic hypertension	%	7.1	7.8	6.3	5.8
Mode of delivery	Vaginal %	51.9	57	58.1	67.0
	Cesarean %	48.1	43	41.9	33.0
Preterm birth	%	8.8	7.4	6.1	5.5
Year of delivery	2003–07 %	34.2	31.3	24.1	28.9
	2008–12 %	39.2	38	32.8	40.9
	2013–15 %	26.7	30.7	43.1	30.2
Maternal race/ethnicity	Caucasian %	65.7	64	70.5	65.9
	Asian %	15.9	12	9.8	7.8
	Black %	5.1	7.8	5	9
	Hispanic %	7.2	10.9	10.3	12.7
	Unknown %	6.1	5.3	4.3	4.7
Education	< 12th grade %	0.2	0.3	**	0.7
	High school diploma %	11.6	20.1	12.4	22.7
	< Bachelor degree %	45.6	51.6	55.3	53.9
	≥Bachelor degree %	42.1	27.4	31.5	22.3
	Unknown %	0.5	0.6	**	0.4
Income	<$50,000 %	6.4	12.3	11.1	15.1
	$50,000–100,000 %	19	24.3	26.2	25.2
	>$100,000 %	46.3	31.1	31.7	28.4
	Unknown %	28.4	32.3	31	31.4
Region of the country	Midwest %	27	26.8	28.3	27.7
	Northeast %	22.8	11.9	7.2	10
	South %	28.5	41.7	39.8	43.8
	West %	21.7	19.4	24.7	18.5
	Unknown %	**	0.2	0	0.1