The files were matched to include the same time period as the above plus an additional nine months in order to capture all of the births from the original cohort of women. This analysis was done using the data for the 28,274 women for whom birth records matched the prenatal records and therefore inferences apply only to women who meet the same criteria. The differences between these women and the women in the original cohort who did not have matching birth records, should be analyzed before results are generalized to the original cohort. The race categories used in this analysis are black and non- black. The prenatal file only asks whether a woman's race is white, black, or other.
Preliminary analysis shows that the other category is more similar to whites than to blacks.
Therefore, in this analysis I grouped whites and other races into the non-black category. Blacks have historically had higher rates of low birth weight births. This relationship of blacks having lower birth weight babies is consistent within the smoking population as well. For this analysis, smokers were defined as those reporting they smoked at least ten cigarettes a day on the Healthy Start screen. As shown in Table 1, for all smoking women the low birth weight rate was 0.1228 which compares to the non-smoking low birth weight rate of 0.1014.