In our Infant Care Project we integrate prenatal, substance abuse, and child services for pregnant women who are abusing drugs and their children. Three groups are identified to study the intervention and the relative contributions of biological and environmental factors: women recruited prenatally (early intervention), those identified postnatally (late), and a matched comparison group with no known drug use.

Prenatal drug exposure is predictive of lower birth weight (F=12.1; p<.0001) and gestational age (F=9.5; p<.0001), regardless of early versus late intervention. Efficacy for the integrated prenatal intervention is evident in the 12 month child developmental data. In post hoc t-test, mental and motor indices are not different between the prenatally recruited child group and the comparison group; both are significantly higher than the late(recruited at birth) intervention group (all p<.05). At 24 months, there are no group differences on the mental index and a trend only (F= 2.9; p<.10) suggesting a difference between the early and late groups on the motor scale.

By 24 months, the effects of the home environment are evident. Although the HOME (adequacy of the caregiving context) score is not associated with child developmental scores at 12 months of age, by 24 months it is significantly predictive of the mental scores (r=.43; p<.05) across all three groups.

It can be argued that women identified prenatally comprise a lower risk group. Nonetheless, we find that the importance of drug exposure and prenatal intervention is clearly evident in birth outcomes and in 12 month development. It is also apparent that the subsequent effects of the home environment are powerful and can obscure the influence of biological factors. The finding suggest that intervention programs need to continue beyond birth and address caregiving influences as well as biological risk.