Emmalee S. Bandstra

Prenatal Drug Exposure: Infant and Toddler Outcomes

ABSTRACT This manuscript provides an overview of the current scientific literature on the impact of maternal drug use, specifically opioids and cocaine, during pregnancy on the acute and long-term outcomes of infants and toddlers from birth through age 3 years. Emphasis with regard to opioids is placed on heroin and opioid substitutes used to treat opioid addiction, including methadone, which has long been regarded as the standard of care in pregnancy, and buprenorphine, which is increasingly being investigated and prescribed as an alternative to methadone. Controlled studies comparing methadone at high and low doses, as well as those comparing methadone with buprenorphine, are highlighted and the diagnosis and management of neonatal abstinence syndrome is discussed. Over the past two decades, attention of the scientific and lay communities has also been focused on the potential adverse effects of cocaine and crack cocaine, especially during the height of the cocaine epidemic in the United States. Herein, the findings are summarized from prospective studies comparing cocaine-exposed with non-cocaine-exposed infants and toddlers with respect to anthropometric growth, infant neurobehavior, visual and auditory function, and cognitive, motor, and language development. The potentially stigmatizing label of the so-called “crack baby” preceded the evidence now accumulating from well-designed prospective investigations that have revealed less severe sequelae in the majority of prenatally exposed infants than originally anticipated. In contrast to opioids, which may produce neonatal abstinence syndrome and infant neurobehavioral deficits, prenatal cocaine exposure appears to be associated with what has been described as statistically significant but subtle decrements in neurobehavioral, cognitive, and language function, especially when viewed in the context of other exposures and the caregiving environment which may mediate or moderate the effects. Whether these early findings may herald more significant learning and behavioral problems during school-age and adolescence when the child is inevitably confronted with increasing social and academic challenges is the subject of ongoing longitudinal research.

Longitudinal influence of prenatal cocaine exposure on child language functioning.

The present study estimates the longitudinal effects of in utero cocaine exposure on language functioning at 3, 5 and 7 years of age in an urban sample of 443 full-term children (236 cocaine-exposed and 207 noncocaine-exposed) participating in the Miami Prenatal Cocaine Study. The sample was enrolled prospectively at birth, with documentation of prenatal drug exposure status through maternal interview and urine and meconium toxicology assays. Language functioning was measured at ages 3 and 5 years using the Clinical Evaluation of Language Fundamentals-Preschool (CELF-P) and at age 7 years using the Core Language Domain of the NEPSY: A Developmental Neuropsychological Assessment. Longitudinal Generalized Linear Model and Generalized Estimating Equations (GLM/GEE) analyses revealed an association between prenatal cocaine exposure and deficits in total language functioning after statistically controlling for child sex, visit age, prenatal exposure to alcohol, marijuana and tobacco and over 20 additional medical and sociodemographic covariates drawn from potentially confounding influences assessed at birth and follow-up visits (D=-0.17; 95% CI=-0.32, -0.03; P=.019). The link from prenatal cocaine exposure to later language deficits does not appear to be mediated by cocaine-associated deficits in birth weight, length or head circumference. Overall, the evidence tends to support an inference of a stable cocaine-specific effect on indicators of language functioning during early childhood through age 7 years.

Massage effects on cocaine-exposed preterm neonates

Thirty preterm cocaine-exposed preterm neonates (mean gestational age 30 wks, mean birth weight = 1212g, mean intensive care unit duration = 18 days) were randomly assigned to a massage therapy or a control group as soon as they were considered medically stable. Group assignment was based on a random stratification of gestational age, birth weight, intensive care unit duration, and entry weight into the study. The treatment group (N = 15) received massages for three 15-minute periods 3 consecutive hours for a 10-day period. Findings suggested that the massaged infants (1) averaged 28% greater weight gain per day (33 vs 26 g) although the groups did not differ in intake (calories or volume), (2) showed significantly fewer postnatal complications and stress behaviors than did control infants, and (3) demonstrated more mature motor behaviors on the Brazelton examination at the end of the 10-day study period. J Dev Behav Pediatr 14:318–322, 1993. Index terms: massage, cocaine, preterm, intervention.

Maternal Cocaine Use: Estimated Effects on Mother-Child Play Interactions in the Preschool Period

ABSTRACT. The study objective was to evaluate the quality of parent-child interactions in preschool-aged children exposed prenatally to cocaine. African-American mothers and their full-term newborns (n = 343) were enrolled prospectively at birth and classified as either prenatally cocaine-exposed (n = 157) or non–cocaine-exposed (n = 186) on the basis of maternal self-report and bioassays. Follow-up evaluations at 3 years of age (mean age, 40 mo) included a videotaped dyadic play session and maternal interviews to assess ongoing drug use and maternal psychological distress. Play interactions were coded using a modified version of Egeland et al’s Teaching Task coding scheme. Regression analyses indicated cocaine-associated deficits in mother-child interaction, even with statistical adjustment for multiple suspected influences on interaction dynamics. Mother-child interactions were most impaired in cocaine-exposed dyads when the mother continued to report cocaine use at the 3-year follow-up. Multivariate profile analysis of the Egeland interaction subscales indicated greater maternal intrusiveness and hostility, poorer quality of instruction, lower maternal confidence, and diminished child persistence in the cocaine-exposed dyads.

Impact of Prenatal Cocaine Exposure on Attention and Response Inhibition as Assessed by Continuous Performance Tests

Objective: This study examined the influence of prenatal cocaine exposure on attention and response inhibition measured by continuous performance tests (CPTs) at ages 5 and 7 years. Methods: The baseline sample consisted of 253 cocaine-exposed and 223 non–cocaine-exposed children enrolled prospectively at birth and assessed comprehensively through age 7 years in the longitudinal Miami Prenatal Cocaine Study. This report includes a subsample of 415 children (219 cocaine-exposed, 196 non–cocaine-exposed) who completed at least one CPT assessment at ages 5 and/or 7 years. Prenatal cocaine exposure was measured by maternal self-report and maternal and infant bioassays. Deficits in attention and response inhibition are estimated in relation to prenatal cocaine exposure using generalized estimating equations within the general linear model. Results: Results indicate cocaine-associated increases in omission errors at ages 5 and 7 as well as increases in response times for target tasks (i.e., slower reaction times) and decreased consistency in performance at age 7. There were no demonstrable cocaine-associated deficits in commission errors. Estimates did not change markedly with statistical adjustment for selected prenatal and postnatal covariates. Conclusion: Evidence supports cocaine-associated deficits in attention processing through age 7 years.

Severity of Prenatal Cocaine Exposure and Child Language Functioning Through Age Seven Years: A Longitudinal Latent Growth Curve Analysis

The current study estimates the longitudinal effects of severity of prenatal cocaine exposure on language functioning in an urban sample of full-term African-American children (200 cocaine-exposed, 176 noncocaine-exposed) through age 7 years. The Miami Prenatal Cocaine Study sample was enrolled prospectively at birth, with documentation of prenatal drug exposure status through maternal interview and toxicology assays of maternal and infant urine and infant meconium. Language functioning was measured at ages 3 and 5 years using the Clinical Evaluation of Language Fundamentals–Preschool (CELF-P) and at age 7 years using the Core Language Domain of the NEPSY: A Developmental Neuropsychological Assessment. Longitudinal latent growth curve analyses were used to examine two components of language functioning, a more stable aptitude for language performance and a time-varying trajectory of language development, across the three time points and their relationship to varying levels of prenatal cocaine exposure. Severity of prenatal cocaine exposure was characterized using a latent construct combining maternal self-report of cocaine use during pregnancy by trimesters and maternal and infant bioassays, allowing all available information to be taken into account. The association between severity of exposure and language functioning was examined within a model including factors for fetal growth, gestational age, and IQ as intercorrelated response variables and childs age, gender, and prenatal alcohol, tobacco, and marijuana exposure as covariates. Results indicated that greater severity of prenatal cocaine exposure was associated with greater deficits within the more stable aptitude for language performance (D = −0.071, 95% CI = −0.133, −0.009; p = 0.026). There was no relationship between severity of prenatal cocaine exposure and the time-varying trajectory of language development. The observed cocaine-associated deficit was independent of multiple alternative suspected sources of variation in language performance, including other potential responses to prenatal cocaine exposure, such as childs intellectual functioning, and other birth and postnatal influences, including language stimulation in the home environment.

Learning Disabilities and Intellectual Functioning in School-Aged Children With Prenatal Cocaine Exposure

Risk for developing a learning disability (LD) or impaired intellectual functioning by age 7 was assessed in full-term children with prenatal cocaine exposure drawn from a cohort of 476 children born full term and enrolled prospectively at birth. Intellectual functioning was assessed using the Wechsler Intelligence Scale for Children–Third Edition (Wechsler, 1991) short form, and academic functioning was assessed using the Wechsler Individual Achievement Test (WIAT; Wechsler, 1993) Screener by examiners blind to exposure status. LDs were categorized based on ability-achievement discrepancy scores, using the regression-based predicted achievement method described in the WIAT manual. The sample in this report included 409 children (212 cocaine-exposed, 197 non-cocaine-exposed) from the birth cohort with available data. Cumulative incidence proportions and relative risk values were estimated using STATA software (Statacorp, 2003). No differences were found in the estimate of relative risk for impaired intellectual functioning (IQ below 70) between children with and without prenatal cocaine exposure (estimated relative risk = .95; 95% confidence interval [CI] = 0.65, 1.39; p = .79). The cocaine-exposed children had 2.8 times greater risk of developing a LD by age 7 than non-cocaine-exposed children (95% CI = 1.05, 7.67; p = .038; IQ ≥ 70 cutoff). Results remained stable with adjustment for multiple child and caregiver covariates, suggesting that children with prenatal cocaine exposure are at increased risk for developing a learning disability by age 7 when compared to their non-cocaine-exposed peers.

Enrolling and retaining mothers of substance-exposed infants in drug abuse treatment

This study provided an experimental test of a drug abuse treatment enrollment and retention intervention in a sample of 103 Black mothers of substance-exposed infants. Significantly more women assigned to the Engaging Moms Program enrolled into drug abuse treatment than did women assigned to the control condition (88% vs. 46%). Sixty-seven percent of participants in the Engaging Moms Program received at least 4 weeks of drug abuse treatment compared with 38% of the control women. However, there were no differences between the groups 90 days following treatment entry. Logistic regressions revealed that readiness for treatment predicted both short-term and long-term treatment retention. The Engaging Moms Program has considerable promise in facilitating treatment entry and short-term retention, but it did not influence long-term retention.

Influence of prenatal cocaine exposure on full-term infant neurobehavioral functioning

This study investigated infant neurobehavioral functioning during the newborn period in 334 full-term, African American neonates (187 cocaine exposed, 147 non-cocaine exposed) enrolled prospectively at birth, with documentation of drug exposure status through maternal interview and urine and meconium toxicology assays. Infants were assessed using the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) during the newborn period (0-6 postnatal days). Findings from multivariate profile analyses support a consistent, modest effect of prenatal cocaine exposure on neurobehavioral functioning in full-term neonates. All of the BNBAS cluster scores, with the exception of abnormal reflexes, were similarly affected, sharing a common slope (D=-0.14; 95% CI=-0.27, -0.003; P=.046) representing a -0.14 point difference between cocaine-exposed and non-cocaine-exposed infants after controlling for prenatal exposure to alcohol, tobacco, and marijuana (ATM); maternal age, education, employment, primigravida status, and prenatal care visits; and infant sex and postnatal age in days. Fetal growth was also related to neurobehavioral functioning and, in part, mediated the relationship between cocaine exposure and the BNBAS cluster scores. Cocaine exposure during each trimester similarly influenced infant neurobehavioral profiles, with cocaine-associated deficits most pronounced in infants with exposure in all three trimesters. Results from qualitative and quantitative urine and meconium bioassay indicators further substantiated these results. Findings, while significant, represent modest effect sizes in full-term infants.

Influence of Prenatal Cocaine Exposure on Early Language Development: Longitudinal Findings from Four Months to Three Years of Age

ABSTRACT. The influence of prenatal cocaine exposure on children’s language functioning was evaluated longitudinally at six time points from 4 months to 3 years of age. The Miami Prenatal Cocaine Study prospectively enrolled 476 full-term African-American infants at birth, categorized as cocaine-exposed (n = 253) or non-cocaine-exposed (n = 223) by maternal self-report and bioassays (maternal/infant urine, meconium). The Bayley Scales of Infant Development, scored using the Kent Scoring Adaptation for language, was administered at 4, 8, 12, 18, and 24 months. The Clinical Evaluation of Language Fundamentals-Preschool was administered at 3 years. In longitudinal analyses using Generalized Estimating Equations, cocaine-exposed children had lower overall language skills than non-cocaine-exposed children (D = −0.151; 95% CI = −0.269, −0.033;p = .012). Longitudinal findings remained stable after evaluation of potential confounding influences including other prenatal substance exposures and sociodemographic factors. Preliminary evidence also indicated possible mediation through an intermediary effect involving cocaine-associated deficits in fetal growth.