TABLE 1.

Study exclusion criteria and final sample

Exclusion Criteria	Stillbirths	Live births
Records of birth events within Ohio, 2006–2010	4,622	751,123
Missing gestational age, gestational sge < 20 weeks, or gestational age > 42 weeks	52	2,910
Birth weight <350 grams	954	366
Chromosomal anomalies	128	685
Multiple gestation	86	26,995
Residence outside of Ohio	113	13,057
Final study set	3,090	707,110