Table 1 Demographic Characteristics

Age at Index Delivery (years)

213

< 0.001

< 25

6

1.3

25

8.4

11

3.5

6

9.8

23

7.9

25–30

49

10.3

108

36.1

64

20.4

20

32.8

114

39.0

31–35

176

37.1

72

24.1

99

31.6

25

41.0

104

35.6

36–40

201

42.4

60

20.1

98

31.3

8

13.1

44

15.1

> 40

42

8.9

34

11.4

41

13.1

2

3.3

7

2.4

Gestational Age at Index Delivery (weeks)

68

< 0.001

< 28

2

0.4

0

0.0

3

1.0

0

0.0

2

0.7

29–36

46

9.7

33

11.0

77

24.6

6

9.8

50

17.1

37–40

391

82.5

216

72.2

217

69.3

47

77.0

209

71.6

> 40

35

7.4

50

16.7

16

5.1

8

13.1

31

10.6

Social Vulnerability Index (SVI)

354

< 0.001

Low-Medium

350

73.8

244

81.6

223

71.2

9

14.8

61

20.9

High

124

26.2

55

18.4

90

28.8

52

85.2

231

79.1

Race & Ethnicity

973

< 0.001

White

330

69.6

297

99.3

261

83.4

6

9.8

14

4.8

Asian

39

8.2

1

0.3

13

4.2

3

4.9

14

4.8

Black/African American

28

5.9

1

0.3

7

2.2

10

16.4

127

43.5

Hispanic/Latina

38

8.0

0

0.0

13

4.2

37

60.7

129

44.2

Other

39

8.2

0

0.0

19

6.1

5

8.2

8

2.7

Health Insurance

960

< 0.001

Private

419

88.4

24

8.0

273

87.2

4

6.6

32

11.0

Public

33

7.0

267

89.3

24

7.7

55

90.2

253

86.6

None

22

4.6

8

2.7

16

5.1

2

3.3

7

2.4

Pre-pregnancy BMI

174

< 0.001

< 30

317

66.9

162

54.2

201

64.2

24

39.3

90

30.8

30–34.9

83

17.5

90

30.1

70

22.4

25

41.0

100

34.2

35–39.9

24

5.1

25

8.4

19

6.1

4

6.6

51

17.5

>/= 40

9

1.9

13

4.3

8

2.6

6

9.8

41

14.0

Missing

41

8.6

9

3.0

15

4.8

2

3.3

10

3.4

Third-trimester EFW

21

< 0.01

< 25th Percentile

12

2.5

1

0.3

11

3.5

1

1.6

10

3.4

25-75th Percentile

194

40.9

8

2.7

58

18.5

23

37.7

165

56.5

75th Percentile

56

11.8

0

0.0

14

4.5

8

13.1

40

13.7

Missing

212

44.7

290

97.0

230

73.5

29

47.5

77

26.4