Executive functioning at ages 5 and 7 years in children with prenatal cocaine exposure.

This prospective longitudinal study evaluated the effect of prenatal cocaine exposure (PCE) on executive functioning in 5- and 7-year-old children. In total, 154 pregnant cocaine users, identified by urine toxicology and structured interviews, were matched to 154 nonusers. Children were assessed by certified masked evaluators, and caregivers were interviewed by experienced staff during home visits. In approximately 90% of the surviving sample tested at ages 5 and 7 years, structural equation modeling demonstrated that an increased head circumference at birth (adjusted for gestation) significantly predicted better performance on executive functioning, and that PCE was indirectly related to executive functioning through its significant negative effect on head circumference at birth. At age 5 years, quality of environment also predicted executive functioning, and the R(2) for the total model was 0.24. At 7 years, caregiver functioning predicted quality of environment, which in turn was positively related to executive functioning, and girls had better executive functioning. The total model at age 7 years accounted for 30% of the variance in executive functioning.

Predicting caregiver-reported behavior problems in cocaine-exposed children at 3 years.

Predictors of caregiver-reported behavior problems for 3-year-olds with prenatal cocaine exposure (PCE) and matched controls were examined using structural equation modeling. We tested whether PCE had a direct effect on child behavior problems in a model that included other prenatal drug exposure, child sex, caregiver depression, and the quality of the child's home environment. The sample (N = 256) was drawn from a longitudinal, prospective study of children of (predominantly crack) cocaine-using women and controls matched on race, socioeconomic status, parity, and pregnancy risk. Child Behavior Problems was modeled as a latent variable composed of the 48-item Conners' Parent Report Scale Conduct Problem and Impulsive-Hyperactive scales and the Eyberg Child Behavior Inventory Intensity scale. Caregiver depression was the only significant predictor of Child Behavior Problems. Mean levels of caregiver self-reported depression and reported child behavior problems did not differ between groups. Mean depression scores were well above the recommended clinical cutoff while mean child behavior problems scores were within normal limits. The model explained 21% of the variance in caregiver-reported child behavior problems in our sample of rural African American, low SES youngsters. Non-maternal caregivers of cocaine-exposed children had significantly lower mean depression scores and mean child behavior problems ratings for 2 of 3 scales used in the study compared to biological mothers of children with PCE and controls. For all groups, much larger proportions of children were rated as having clinically significant behavior problems than would be expected based on the prevalence of behavior problems in the general population.

Outcome from a prospective, longitudinal study of prenatal cocaine use: preschool development at 3 years of age.

OBJECTIVE: To determine the effects of prenatal cocaine exposure on child development. METHODS: This prospective, longitudinal study recruited 154 pregnant cocaine users who were matched on race, parity, socioeconomic status, and perinatal risk to 154 noncocaine users. Drug use status was determined by maternal history and urine screening. At 3 years of age, the child subjects were assessed by an evaluator blinded to maternal drug use history. During a home visit at age 3, caregiver, family, and home assessments were administered. RESULTS: Structural equation modeling showed a direct effect of the amount of prenatal cocaine exposure on the adjusted birth head circumference which in turn directly affected preschool development. CONCLUSIONS: We could not demonstrate a direct effect of prenatal cocaine exposure on preschool development, a result that is consistent with that of earlier work and now extending findings to age 3. However, cocaine continued to exert an indirect effect on development through its direct effect on the head circumference at birth.

Relative ability of biologic specimens and interviews to detect prenatal cocaine use.

For this study, we recruited women admitted to our labor and delivery service, enrolling all consenting patients with a history of prenatal cocaine use and the next admission with no recorded use. During the immediate postpartum period, experienced researchers conducted private, structured interviews to obtain details of prenatal cocaine use and to identify a priori exclusion criteria (other illicit drug use, high alcohol use and chronic illnesses and medications). Specific protocols were used to collect amniotic fluid, cord blood, infant urine, meconium and maternal hair. All specimens were analyzed blind with respect to exposure using gas chromatography/mass spectrometry. Of 115 subjects, 46 had one or more biologic specimens positive for cocaine metabolites and five admitted prenatal use, but had negative specimens. Of these 51 identified as users by any method, 38 admitted, 32 were positive for urine, 28 for hair and 25 for meconium. Of the 38 admitters, 87% had positive specimens; of the 77 denying use, 17% were positive. Urine was most frequently positive in identified users, 67% overall and 62% of users who denied. Hair was next, positive in 65% of all users and 50% of users who denied. Of the 13 subjects who denied use but were positive on at least one specimen, four were identified solely by urine, two only by hair and one only by meconium. Self-report identified five users with all negative specimens. Although no one method identified all users, the single method that maximally identified users was detailed history taken by experienced interviewers.

Cocaine exposure and developmental outcome from birth to 6 months.

The theoretical framework for many of the early studies of prenatal cocaine exposure has been rooted in the basic concepts of teratology/developmental toxicology. Few have published longitudinal analyses of the complex interplay between the relative effects of prenatal cocaine exposure and perinatal and environmental factors on development. The purpose of this paper was to use structural equation modeling to describe the direct and indirect effects of prenatal drug exposure on developmental outcome from birth to age 6 months. Key variables considered for study include prenatal drug exposure, perinatal medical characteristics, maternal/caregiver/family characteristics, the home environment, and neurobehavioral outcomes. We prospectively enrolled 154 predominantly crack-using women. A priori exclusion criteria included: <18 years old, major illnesses diagnosed prior to pregnancy, chronic use of legal drugs, and any use of illicit drugs other than cocaine and marijuana. From the pool of noncocaine users, 154 subjects were matched to users on pregnancy risk, parity, race, and socioeconomic status. At the end of each trimester, experienced staff conducted private interviews prompting memory of amount and timing of past drug use. Urine specimens were collected at two unanticipated times; positive screens were confirmed by gas chromatography/mass spectroscopy. Measures analyzed include medical (birth) and developmental (birth, 1 month, 6 months) assessments, all performed by blinded evaluators, as well as caregiver characteristics and environmental factors (birth, 1 month). A series of four theoretical models was tested, one for each time point (birth, 1 month, 6 months) and a longitudinal model spanning birth to 6 months. Key findings include direct effects of prenatal cocaine exposure on development at birth in the birth model and on development at birth and 6 months in the longitudinal model. In addition, indirect effects of prenatal cocaine exposure were identified on development at birth, 1 month, and 6 months, mediated through the prenatal use of alcohol and tobacco and the birth head circumference. Implications of these and other findings, including the advantages and limitations of structural equation modeling, are discussed.