Table 1 Prevalence of isolated CLP affected pregnancies per 10,000 births (95% CI)

4.88 (4.79–4.97)

5.02 (4.80–5.24)

4.85 (4.64–5.08)

5.11 (4.88–5.34)

4.63 (4.41–4.85)

4.71 (4.49–4.94)

4.94 (4.72–5.17)

0.027

Maternal Age

Less than 20

5.29 (4.87–5.75)

5.23 (4.3–6.3)

4.93 (4–6.02)

5.23 (4.23–6.39)

5.64 (4.58–6.87)

4.94 (3.91–6.15)

5.91 (4.74 7.28)

0.428

20 to 24

5.48 (5.26–5.71)

6 (5.48–6.56)

5.37 (4.86–5.91)

5.67 (5.13–6.24)

5.19 (4.67–5.75)

5.12 (4.59–5.69)

5.46 (4.91–6.06)

0.074

25 to 29

5 (4.83–5.18)

4.93 (4.53–5.35)

5.2 (4.85–5.72)

5.27 (4.85–5.72)

4.78 (4.37–5.21)

4.58 (4.18–5.02)

5.24 (4.81–5.02)

0.080

30 to 34

4.46 (4.3–4.62)

4.54 (4.16–4.96)

4.3 (3.92–4.71)

4.67 (4.27–5.09)

4.37 (3.98–4.78)

4.56 (4.17–4.99)

4.3 (3.92–4.7)

0.654

35 to 39

4.5 (4.298–4.73)

4.34 (3.8–4.93)

4.5 (3.96–5.09)

4.84 (4.29–5.45)

3.94 (3.44–4.49)

4.57 (4.03–5.16)

4.79 (4.25–5.39)

0.492

Over 40

5.18 (4.68–5.71)

6.37 (5.03–7.95)

4.9 (3.75–6.29)

5.34 (4.15–6.77)

4.3 (3.25–5.59)

5.23 (4.06–6.63)

5.01 (3.89–6.35)

0.208

p-value^҂

<  0.001

0.001

0.006

0.028

<  0.001

0.342

0.003

–

Maternal Race/Ethnicity

NH^a White

5.51 (5.38–5.65)

5.71 (5.39–6.05)

5.48 (5.16–5.82)

5.73 (5.4–6.08)

5.37 (5.04–5.7)

5.28 (4.96–5.63)

5.48 (5.15–5.82)

0.132

NH Black

2.89 (2.71–3.08)

2.93 (2.5–3.42)

2.8 (2.38–3.27)

2.95 (2.52–3.44)

2.86 (2.43–3.35)

2.45 (2.05–2.91)

3.34 (2.86–3.82)

0.122

NH Asian

3.84 (3.52–4.17)

3.81 (3.09–4.64)

4.36 (3.58–5.27)

3.73 (3–4.59)

3.09 (2.43–3.88)

4.38 (3.54–5.34)

3.65 (2.88–4.55)

0.135

Hispanic

4.82 (4.64–5.01)

4.89 (4.45–5.36)

4.8 (4.36–5.27)

5.23 (4.76–5.72)

4.39 (3.96–4.87)

4.81 (4.36–5.28)

4.80 (4.36–5.28)

0.181

NH Others

6.34 (5.78–6.94)

6.41 (5.07–8)

5.42 (4.19–6.89)

7.02 (5.62–8.67)

6.53 (5.17–8.12)

5.72 (4.45–7.23)

6.93 (5.54–8.57)

0.436

Maternal Education

< 12 years

6.09 (5.8–6.38)

6.28 (5.63–6.99)

5.49 (4.86–6.17)

6.32 (5.62–7.07)

5.81 (5.13–6.56)

5.74 (5.04–6.51)

6.98 (6.19–7.85)

0.286

> 12 years

4.71 (4.61–4.81)

4.82 (4.59–5.06)

4.75 (4.51–4.99)

4.94 (4.7–5.19)

4.47 (4.24–4.7)

4.58 (4.34–4.82)

4.69 (4.46–4.93)

0.099

Smoking before Pregnancy^⁑

No

4.62 (4.53–4.71)

4.74 (4.52–4.97)

4.58 (4.36–4.81)

4.81 (4.58–5.04)

4.48 (4.26–4.71)

4.41 (4.19–4.64)

4.69 (4.46–4.92)

0.114

1–5

6.82 (6.1–7.61)

7.05 (5.48–8.94)

6.76 (5.17–8.69)

7.77 (5.99–9.9)

5.36 (3.85–7.27)

6.62 (4.84–8.83)

7.34 (5.31–9.89)

0.440

6–10

7.76 (7.08–8.5)

6.96 (5.58–8.58)

7.41 (5.92–9.15)

8.24 (6.61–10.15)

7.12 (5.54–9.01)

8.55 (6.7–10.75)

8.99 (6.92–11.48)

0.109

11–20

8.53 (7.81–9.3)

8.22 (6.71–9.96)

7.91 (6.39–9.7)

8.91 (7.22–10.88)

6.66 (5.13–8.51)

10.14 (8.1–12.53)

10.14 (7.94–12.77)

0.121

> 20

7.76 (6.47–9.23)

8.6 (5.99–11.96)

7.85 (5.34–11.15)

7.42 (4.89–10.79)

5.74 (2.75–10.56)

7.53 (3.89–13.15)

8.73 (4.51–15.24)

0.672

p-value^҂

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

<  0.001

–

BMI

Underweight

4.87 (4.36–5.42)

4.75 (3.65–6.06)

4.4 (3.32–5.72)

5.16 (3.95–6.63)

4.83 (3.63–6.31)

5.4 (4.06–7.05)

4.78 (3.5–6.38)

0.584

Normal

4.45 (4.32–4.59)

4.59 (4.27–4.92)

4.71 (4.38–5.06)

4.47 (4.15–4.82)

4.37 (4.04–4.71)

4.2 (3.87–4.55)

4.32 (3.99–4.68)

0.038

Overweight

4.46 (4.49–4.84)

4.89 (4.47–5.35)

4.47 (4.06–4.91)

4.76 (4.34–5.21)

4.23 (3.83–4.66)

4.63 (4.21–5.09)

4.99 (4.56–5.45)

0.805

Obesity I

5.27 (5.03–5.52)

5.63 (5.02–6.29)

4.8 (4.24–5.42)

5.59 (5.37–6.67)

5.21 (4.63–5.84)

5.02 (4.45–5.64)

5.01 (4.46–5.62)

0.204

Obesity II

5.99 (5.63–6.37)

6.46 (5.53–7.5)

6.3 (5.39–7.32)

6.57 (5.65–7.6)

4.91 (4.13–5.79)

5.4 (4.59–6.31)

6.35 (5.47–7.32)

0.224

M-Obese^b

6.1 (5.67–6.55)

6.02 (4.96–7.23)

6.26 (5.2–7.48)

6.67 (5.59–7.9)

5.88 (4.88–7.03)

6.04 (5.03–7.19)

5.75 (4.79–6.86)

0.526

p-value^҂

<  0.001

<  0.001

<  0.001

<  0.001

0.001

<  0.001

<  0.001

–

Pre– pregnancy Diabetes

Yes

10.82 (9.48–12.28)

9.18 (6.23–12.02)

8.78 (5.96–12.46)

14.28 (10.63–18.77)

10.12 (7.13–13.95)

12.61 (9.3–16.72)

9.83 (6.99–13.43)

0.503

No

4.82 (4.73–4.91)

4.97 (4.75–5.2)

4.82 (4.6–5.05)

5.01 (4.79–5.25)

4.58 (4.36–4.8)

4.63 (4.41–4.86)

4.88 (4.65–5.11)

0.111

Pre– pregnancy Hypertension

Yes

6.38 (5.69–7.12)

5.85 (4.18–7.97)

6.44 (4.73–8.56)

7.28 (5.51–9.43)

6.74 (5.09–8.75)

6.67 (5.2–8.56)

5.42 (4.07–7.08)

0.655

No

4.84 (4.75–4.93)

4.99 (4.77–5.22)

4.83 (4.61–5.05)

5.06 (4.83–5.29)

4.58 (4.37–4.81)

4.66 (4.44–4.89)

4.92 (4.69–5.15)

0.151

Infertility Treatment Use

No Treatment

4.86 (4.77–4.96)

4.99 (4.77–5.22)

4.84 (4.62–5.07)

5.09 (4.86–5.32)

4.63 (4.42–4.86)

4.7 (4.47–4.93)

4.91 (4.69–5.15)

0.048

Fertility Enhancing Drugs

4.52 (3.48–5.78)

4.12 (1.97–7.58)

6.48 (3.7–10.52)

4.9 (2.53–8.56)

3.45 (1.49–6.8)

4.03 (1.84–7.65)

3.99 (1.82–7.58)

0.413

Asst. Reproductive Technology

6.18 (5.23–7.25)

7.92 (5.22–11.53)

5.41 (3.3–8.35)

6.67 (4.36–9.77)

5.1 (3.2–7.73)

5.89 (3.81–8.69)

6.38 (4.33–9.05)

0.523

Both

6.59 (4.18–9.89)

5.52 (1.14–1.16)

3.41 (4.14–12.34)

5.09 (1.05–14.88)

5.13 (1.05–14.98)

12.91 (5.19–26.59)

7.74 (2.51–18.06)

0.171

Payment Source for Delivery

Medicaid

5.46 (5.31–5.61)

5.71 (5.36–6.09)

5.35 (5.01–5.72)

5.84 (5.47–6.23)

5.12 (4.77–5.49)

5.17 (4.81–5.55)

5.53 (− 5.16–5.92)

0.149

Private Insurance

4.42 (4.29–4.54)

4.48 (4.19–4.79)

4.48 (4.18–4.79)

4.51 (4.21–4.82)

4.23 (3.94–4.53)

4.28 (3.99–4.6)

4.51 (4.21–4.83)

0.585

Self– pay

4.85 (4.42–5.31)

4.75 (3.76–5.91)

4.41 (3.45–5.56)

4.49 (3.52–5.65)

4.49 (3.52–5.65)

5.3 (4.18–6.63)

4.97 (3.89–6.26)

0.523

Others

4.85 (4.38–5.34)

4.36 (3.38–5.53)

4.88 (3.82–6.15)

5.12 (4.03–6.42)

4.94 (3.81–6.3)

5.22 (4.02–6.65)

4.62 (3.51–5.97)

0.632

Previous Preterm Birth

Yes

7.04 (6.46–7.64)

6.47 (5.12–8.07)

6.96 (5.58–8.57)

8.21 (6.75–9.89)

6.15 (4.91–7.62)

6.21 (4.95–7.7)

8.12 (6.7–9.77)

0.513

No

4.80 (4.71–4.89)

4.96 (4.74–5.19)

4.79 (4.57–5.01)

4.99 (4.76–5.22)

4.57 (4.35–4.8)

4.66 (4.43–4.89)

4.80 (4.58–5.04)

0.093

Sex of Infant

Male

5.96 (5.82–6.1)

6.92 (5.95–6.65)

5.81 (5.48–6.16)

6.15 (5.81–6.51)

5.6 (5.27–5.95)

5.79 (5.45–6.15)

6.08 (5.74–6.45)

0.239

Female

3.75 (3.64–3.87)

3.68 (3.41–3.96)

3.85 (3.57–4.14)

4.02 (3.74–4.32)

3.61 (3.34–3.9)

3.59 (3.31–3.88)

3.74 (3.47–4.04)

0.479