Skip to main content
. Author manuscript; available in PMC: 2007 Sep 27.
Published in final edited form as: Epidemiology. 2005 May;16(3):323–327. doi: 10.1097/01.ede.0000158801.04494.52

TABLE 2.

Pregnancy Duration (Gestational Length, in Weeks) and Risk of Preterm Delivery (<37 wk Gestation) Among Pregnant Women Exposed and Unexposed to September 11, 2001, With Differences, Odds Ratios, and 95% Confidence Intervals Derived From Generalized Linear Mixed Models

Gestational Length
Preterm Delivery
Exposed (n = 606) Mean ± SD Unexposed (n = 1184) Mean ± SD Difference* (95% CI) Exposed (n = 606) No. (%) Unexposed (n = 1184) No. (%) Odds Ratio* (95% CI)
All women 39.6 ± 1.71 39.5 ± 1.8 0.13 (−0.05 to 0.30) 29 (4.8) 82 (6.9) 0.60 (0.36 to 0.98)
Timing of exposure
 1st trimester (n = 587) 39.7 ± 1.2 39.4 ± 2.1 0.22 (−0.08 to 0.53) 5 (2.5) 30 (7.7) 0.26 (0.09 to 0.75)
 2nd trimester (n = 518) 39.4 ± 2.2 39.3 ± 1.9 0.05 (−0.28 to 0.37) 13 (7.4) 29 (8.5) 0.77 (0.34 to 1.73)
 3rd trimester (n = 685) 39.7 ± 1.6 39.7 ± 1.5 0.11 (−0.17 to 0.40) 11 (4.8) 23 (5.1) 0.92 (0.40 to 2.09)
*

Overall estimates are derived from models, including exposure status, trimester at exposure, and household poverty level. Estimates stratified by trimester of exposure are derived from models that include these terms plus interactions between exposure status and trimester at exposure.