Behavior in cocaine-exposed infants and children: association versus causality

Cocaine-exposed infant behavior during Still-Face: risk factor analyses

Prenatal cocaine exposure and the role of gender were evaluated using risk factor analyses to determine whether 6-month-old cocaine-exposed male infants demonstrated greater disruptions in infant-caregiver socioemotional interactions during a Still-Face test. Overall, non-cocaine-exposed infants spent more time looking at toys, compared with cocaine-exposed infants; nonexposed female infants spent more time scanning the environment, compared with nonexposed male infants. When caregiver behavior during the Still-Face was evaluated, differences emerged in amount of time the caregiver spent vocalizing to the infant. She vocalized more to a cocaine-exposed infant compared with a nonexposed one; she reduced vocalizing more during the test if the cocaine-exposed infant was female. An exposure by gender interaction emerged in the amount of change in caregiver vocalizations; however, the overarching hypothesis that male cocaine-exposed infants are at higher risk than nonexposed male, nonexposed female, and cocaine-exposed female infants was not supported. Because this interaction was evident in this cohort at 24 months, future research is needed to determine at what age an interaction begins to emerge in this cohort.

Neurological and developmental outcomes of prenatally cocaine-exposed offspring from 12 to 36 months

Second generation studies of prenatal cocaine exposure failed to find gross deficits after controlling for confounders. Concern remained that exposure could cause subtle deficits. This prospective, cohort study evaluated effects of cocaine on development at 12, 18, 24, and 36 months. From 1991-1993, 361 mother-infant pairs were recruited from the Children's Hospital of New York, Presbyterian Medical Center's prenatal clinic or delivery room suite. Mothers were assigned to the cocaine group based on report of prenatal cocaine use or positive urine toxicology. Control mothers were enrolled from the same clinic and matched for age and socioeconomic status (SES). Women with serious medical problems were excluded from either group. Of the retained cohort, at 12 months, 147 infants were exposed and 89 were unexposed case controls. Both groups were raised in impoverished environments with few supports. Developmental evaluations were conducted blinded to group. Cross-sectional analysis revealed cocaine-related deficits in neurological exams and speech across all time periods, in spite of catch up in weight, length, and head circumference. Overall analysis of development was evaluated using Generalized Estimating Equations regression analysis. Bayley Mental [Badj = -6.5 (CI--9.4, -3.5, p < or = 0.001)] and Psychomotor [Badj = -3.9 (CI--7.4, -0.5, p = 0.02)] Developmental Indices showed deficits after controlling for confounders. Males were more vulnerable to cocaine exposure for height, motor development, and emotional regulation. Dose-response relationships existed for abnormal neurological exams (Ptrends < 0.08), Mental Development Index (MDI) (Ptrend < 0.001), and Psychomotor Development Index (PDI) (Ptrend < 0.001) deficits. Although nonexposed children performed poorly, cocaine-exposed children showed worse performance. Both groups showed declines at 18 months in mental and psychomotor development from which only nonexposed children rebounded. Overall, cocaine exposure adds an additional risk to disadvantaged children's development. Cocaine-exposed children are less resilient to effects of these multiple risks.

Parenting knowledge among substance abusing women in treatment

The purpose of this study was to assess parenting knowledge and beliefs among drug abusing pregnant and recently postpartum women engaged in a comprehensive substance abuse treatment program. The effects of a parenting skills training program for this population were evaluated. A Parenting Skills Questionnaire was developed and administered to a sample of 73 pregnant and drug-dependent women during their first week of substance abuse treatment and again approximately 7 weeks later, following parenting skills training. The questionnaire was designed to assess whether group and individual parenting sessions changed the subjects' knowledge and beliefs in four parenting domains: newborn care, feeding practices, child development and drug abuse during pregnancy. Pre-intervention scores for all parenting domains were low. Post- vs. pre-intervention comparisons showed significant increases in all domain scores after individual and group parenting skills training. Preliminary results obtained from this clinic-based sample suggest that these substance abusing mothers lacked important parenting knowledge and that this knowledge improved after comprehensive substance abuse treatment that included parenting training.

Cocaine: effects of in utero exposure on the fetus and neonate

In North America, an increasing number of babies are prenatally exposed to cocaine, yet the implications of cocaine use during pregnancy are not fully understood. The effects of cocaine are exerted primarily by its influence on aminergic receptors in the central and peripheral nervous systems. Developmental, physiological, and behavioral problems in infants and children are likely outcomes of maternal cocaine abuse, but these findings are confounded by concomitant use of other drugs such as marijuana and cocaine and by factors such as time, dosage, and route of cocaine intake. Different screening options exist for cocaine and its metabolites, including sampling of neonatal urine, hair and meconium need to be considered, as do the sensitivity and the ethical implications of such testing. Clinical management of cocaine-exposed infants requires attention to several issues, including: central nervous system irritation, cardiac anomalies, apnea, and feeding difficulties, as well as infant safety and follow-up postdischarge. Early detection and intervention remain the primary objectives of caring for cocaine-exposed infants.

Adverse effects of fetal cocaine exposure on neonatal auditory information processing

BACKGROUND

Studies with animals have shown that in utero exposure to cocaine interferes with fetal brain development by disrupting the processes of neuronal proliferation, differentiation, and migration, often leading to subsequent neurobehavioral deficits. However, studies with humans have produced inconsistent findings. Although neurobehavioral abnormalities have been observed among cocaine-exposed infants in several studies and in some cases dose-response effects have been found, the specific neurobehaviors affected vary from one study to the next. Researchers studying the effects of fetal cocaine-exposure are faced with many difficult challenges. For example, women who use cocaine typically use other substances in addition to cocaine, many of the methods available for identifying cocaine-exposed neonates are not reliable, and the available methods for assessing cocaine-exposed newborns may not be sufficiently sensitive to detect the subtle effects of cocaine on the developing central nervous system. Despite these difficulties, there is a growing body of research that suggests that fetal cocaine exposure is associated with subsequent language deficits among children exposed in utero. However, it is virtually impossible to disentangle the effects of the impoverished environments in which these children are often raised from the effect, if any, of fetal cocaine exposure. To determine the effects of fetal cocaine exposure independent of postnatal environmental effects, cocaine-exposed neonates would ideally be tested within the first few weeks of birth, and to identify early risks for subsequent language delay, well-researched auditory information processing measures could be used.

OBJECTIVE

The purpose of the present study was to assess the effects of fetal cocaine exposure on neonatal auditory information processing ability. To overcome limitations of some previous studies on the neuroteratogenic effects of cocaine, such as unreliable subject identification techniques, inadequate control over confounding variables, and questionable measures of central nervous system integrity, a valid measure of auditory information processing was used in a rigorous, case-control design.

METHOD

Newborn information processing was assessed using habituation and recovery of head-turning toward an auditory stimulus across the 3 phases of the procedure: familiarization, novelty, and dishabituation. During the familiarization phase, the infant orients and habituates to a repeated word; during the novelty phase, the infant recovers head-turning to a novel word and subsequently habituates to this word; and during the dishabituation phase the infant displays renewed head-turning to the return of the original stimulus. Testing takes approximately 20 minutes. This procedure has been shown previously to discriminate among infants at high-, moderate-, and low-risk for subsequent developmental delay. Twenty-five cocaine-exposed and 25 nonexposed control neonates, identified by meconium analysis, urine analysis, and/or maternal self-report, were tested on the auditory information processing procedure. The majority of infants were tested within the first few days of birth. Cocaine-exposed and control neonates were matched on birth weight, gestational age, Apgar scores, age at testing, and socioeconomic status as reflected by household income. Mothers were matched on age, weight gain, cigarette smoking, and alcohol consumption.

RESULTS

Fetal cocaine exposure was associated with impaired auditory information processing. Both cocaine-exposed and nonexposed control neonates oriented to the familiarization stimulus, but cocaine-exposed neonates displayed impaired habituation. Moreover, cocaine-exposed neonates did not recover or habituate to the novel stimulus or dishabituate to the return of the familiarization stimulus. (ABSTRACT TRUNCATED)

Bolus maternal cocaine administration does not produce a large increase in fetal sheep cerebral cortical glutamate concentration

Human cocaine use during pregnancy may result in postnatal neurologic dysfunction and abnormal behavior. L-Glutamate, the major excitatory neurotransmitter in the brain, plays an important role in cerebral cortical development. An optimal level of glutamate is required for normal neuronal development. We tested whether acute cocaine exposure produces large increases in glutamate release in the intact cerebral cortex of the near-term fetal sheep. Cocaine 3.0 mg kg(-1) IV bolus produced the expected increase in maternal and fetal mean arterial pressure, increase in fetal heart rate, decrease in uterine blood flow, and decrease in fetal arterial blood pO2 (N = 5). The percentage increases in extracellular glutamate concentration in the fetal cerebral cortex measured by in utero microdialysis were 7%, 15%, 17%, 17%, and 43% in each fetus (upper 95% confidence bound for the median = 43%). We conclude that if cocaine increases glutamate concentration in the developing cerebral cortex, the increase in magnitude is small relative to the changes produced by other interventions such as ethanol or umbilical cord occlusion. Mechanisms other than increases in cerebral cortical glutamate concentration probably contribute to the neurologic injury associated with prenatal cocaine exposure.