Table 1.

Risk of term low birth weight by maternal characteristics.

Population characteristic	Number of subjects	Odds ratio (95% confidence interval)
Maternal race/ethnicity
African American	25,004	2.829 (2.740; 2.922)
Asian	53,525	1.866 (1.817; 1.917)
Hispanic	221,177	1.361 (1.333; 1.389)
Multiple/other	10,021	1.384 (1.309; 1.462)
Caucasian	121,174	1.00 (reference)
Missing	4891
Maternal education
Lower than 8th grade	44,475	1.268 (1.230; 1.307)
9th grade to High School	193,557	1.380 (1.351; 1.409)
College (<4 years)	86,203	1.163 (1.134; 1.193)
College (≥4 years)	100,717	1.00 (reference)
Missing	10,840
Median annual income by census block group
≤$30,933	108,408	1.386 (1.355; 1.418)
$30,938–$42,483	108,547	1.224 (1.196; 1.253)
$42,500–$60,179	108,645	1.123 (1.097; 1.150)
≥$60,185	108,742	1.00 (reference)
Missing	1450
Maternal age
<15	568	2.142 (1.778; 2.581)
15 to 19	42,297	1.651 (1.605; 1.699)
20 to 24	100,201	1.263 (1.234; 1.293)
25 to 29	114,540	1.070 (1.045; 1.095)
30 to 34	105,483	1.00 (reference)
35 to 39	58,065	1.076 (1.047; 1.107)
40 to 44	13,856	1.391 (1.329; 1.456)
45 to 49	716	1.823 (1.534; 2.167)
50 and over	66	2.016 (1.161; 3.501)
Chronic hypertension
Yes	1746	2.618 (2.371; 2.891)
No	434,035	1.00 (reference)
Missing	11
Diabetes
Yes	12,340	1.055 (1.006; 1.106)
No	423,441	1.00 (reference)
Missing	11
Preeclampsia
Yes	9875	4.258 (4.089; 4.434)
No	425,913	1.00 (reference)
Missing	4
Primary care
None	1817	3.277 (2.980; 3.603)
After first trimester	59,744	1.264 (1.237; 1.293)
First trimester	371,231	1.00 (reference)
Missing	3000
Parity
Primiparous	179,829	1.533 (1.508; 1.557)
Multiparous	255,768	1.00 (reference)
Missing	195
Smoking during pregnancy (2007–2008 data only)
Yes	3022	1.899 (1.75; 2.062)
No	110,353	1.00 (reference)
Pre-pregnancy body mass index (2007–2008 data only)
≤19.9	13,452	1.917 (1.795; 2.048)
20–24.9	43,415	1.203 (1.135; 1.275)
25–29.9	25,656	1.062 (0.997; 1.131)
30–34.9	11,809	1.00 (reference)
>35	7311	1.074 (0.988; 1.167)
Missing	11,732