Table 1

Characteristics of eligible cohort members assigned exposures and those who were not assigned exposures.

Covariate

Subjects assigned exposure data N = 74,284
Subjects with no exposure data N = 14,849

Maternal age: Mean (SD)

28.6 (5.2)
28.0 (5.1)
Pre-pregnancy weight: Mean (SD)

64.7 (13.7)
66.5 (14.9)
Weight at delivery: Mean (SD)

79.7 (13.9)
81.0 (14.9)
Infant Gender

Male
51.0%
50.6%

Female
49.0%
49.4%
Nulliparous

Yes
45.3%
42.7%

No
54.7%
57.3%
Smoking at delivery

Yes
24.9%
25.8%

No
75.1%
74.2%
Pregnancy complications

Yes
3.9 %
4.1 %

No
96.1 %
95.9 %
Income Quintile

1
21.6%
17.0%

2
20.0%
20.7%

3
19.9%
20.2%

4
21.4%
21.9%

5
17.1%
20.9%
Urban/Rural residence

Urban
74.7%
70.6%

Rural
25.3%
29.4%

Dugandzic et al. Environmental Health: A Global Access Science Source 2006 5:3   doi:10.1186/1476-069X-5-3