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. Author manuscript; available in PMC: 2019 Feb 28.
Published in final edited form as: J Perinatol. 2018 Aug 30;38(11):1457–1465. doi: 10.1038/s41372-018-0205-9

Table 1:

Maternal and Infant Characteristics

Demographic Characteristic Total Fertile Subfertile ART
Total N 345756 332481 4987 8288
Percent % % % %
Age* 18–29
30–34
35–37
38–40
41–42
43+		 48.2
30.2
12.4
6.5
1.8
0.9		 49.7
30.2
11.9
6
1.6
0.7		 13.7
33.5
24.8
17.6
6.6
3.8		 8.8
32.1
24.2
19.6
8.5
6.7
Race/Ethnicity* Hispanic 14 14.4 5.1 3.6
Non-Hispanic White 66.7 66 82.5 84.1
Non-Hispanic Black 8.8 9 3.8 3.2
Non-Hispanic Asian 8.2 8.2 7.4 7.9
Other Non-Hispanic 2.3 2.3 1.2 1.1
Education* < HS/HS graduate
Some college
College graduate		 36.2
22.2
41.6		 37.2
22.4
40.4		 12.8
17.8
69.4		 10
16.1
73.9
Insurance at delivery1* Private
Public
Self-pay		 58.8
40.4
0.8		 57.4
41.8
0.8		 90.2
9
0.8		 95.4
3.4
1.2
Non-gestational diabetes* No
Yes		 98.8
1.2		 98.8
1.2		 98.1
1.9		 97.9
2.1
Chronic hypertension* No
Yes		 98.2
1.8		 98.3
1.7		 97.1
2.9		 96.8
3.2
Parity* 1
2
3+		 57.4
26.7
16		 56.9
26.8
16.3		 58.8
28.2
13		 74.9
19.5
5.6
Method of Delivery* Vaginal
VBAC
Primary CS
Repeated CS		 66.9
1.5
21.8
9.8		 67.4
1.5
21.4
9.7		 55.5
1.9
29.2
13.4		 53.5
0.8
37.1
8.6
Year of birth* 2004
2005
2006
2007
2008
2009
2010		 10.2
19.7
17.7
15.3
13.5
12.2
11.3		 10.3
19.7
17.7
15.3
13.5
12.2
11.2		 14.3
22
19.6
13.5
11.2
10
9.4		 5.2
17.7
17
16.2
14
13.9
16
Infant Characteristics
Infant Sex^ Male
Female		 51.2
48.8		 51.2
48.8		 51
49		 51.4
48.6
Gestational Age (weeks) * Overall2 39.01
(1.76)		 39.02
(1.74)		 38.80 (1.89) 38.67
(2.10)
23–27 weeks
28–33 weeks
34–36 weeks
37–38 weeks
≥39 weeks		 0.2
1.2
4.8
21
72.7		 0.2
1.2
4.8
20.8
73		 0.3
1.7
6.1
24.9
66.9		 0.5
2.4
7.5
23.7
66
Birthweight (grams) * Overall2 3352 (543) 3354 (541) 3360 (572) 3305 (591)
≤1,000 grams
1,001–1,500 grams
1,501–2,500 grams
≥2,501 grams		 0.3
0.4
4.8
94.5
 0.3
0.4
4.7
94.6
 0.4
0.4
5.7
93.5
 0.5
0.8
6.3
92.3
1

Public is a composite of Free care and Public

2

Mean and Standard Deviation

*

Denotes statistical significance at P<0.0001 (for characteristics with more than two strata, the test for significance is across the entire characteristic and not for each strata;

^

p=0.96

VBAC = Vaginal Birth After Cesarean; CS = Cesarean Section