An exploratory study of the variables impacting preterm birth rates in New Mexico

Table 2 Adjusted odds ratios for risk of PTB by demographic and perinatal characteristics, New Mexico, 1991-2005

	Adjusted Odds Ratio	95% Confidence Interval	p value
Maternal Age
Reference age = 25-29
Age Group
<15	1.9	1.47-2.46	<0.0001
15-19	1.22	1.15-1.30	<0.0001
20-24	1.07	1.02-1.13	0.0059
30-34	1.09	1.03-1.15	0.0037
35-39	1.25	1.17-1.35	<0.0001
>40	1.34	1.18-1.52	<0.0001
Maternal Education Level
Reference education level = 9-12 years
Number of years
<9	0.995	0.92-1.07	0.91
13-16	0.89	0.85-0.93	<0.0001
>16	0.82	0.76-0.89	<0.0001
Maternal Ethnicity
Reference ethnicity = White Non-Hispanic
Asian	1.23	1.05-1.43	0.0087
Other	1.49	0.76-2.92	0.2452
White Hispanic	1.05	1.00-1.10	0.0372
Native American	0.88	0.82-0.95	0.0016
Black	1.37	1.22-1.54	<0.0001
Normal Risk Pregnancy and Level of Prenatal Care
Reference level of care = Kotelchuck adequate
Kotelchuck Index
None	4.92	4.53-5.34	<0.0001
Inadequate	2.16	2.02-2.30	<0.0001
Intermediate	0.93	0.85-1.01	0.0728
High	4.95	4.66-5.25	<0.0001
High Risk Pregnancy and Level of Prenatal Care
Kotelchuck Index
None	14.66	12.92-16.64	<0.0001
Inadequate	4.78	4.34-5.26	<0.0001
Intermediate	2.59	2.26-2.97	<0.0001
Adequate	2.31	2.08-2.56	<0.0001
High	8.42	7.83-9.05	<0.0001

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