Increased incidence of intraventricular hemorrhage and developmental delay in cocaine-exposed, very low birth weight infants

Prenatal cocaine exposure and child outcomes: a conference report based on a prospective study from Cleveland

OBJECTIVE

The study aims to describe developmental outcomes from a longitudinal prospective cohort (Cleveland study) of prenatally cocaine-exposed (CE) infants.

METHODS

Two hundred eighteen CE and 197 nonexposed infants were enrolled at birth and followed through mid-adolescence. Birth CE status was determined by interview and biologic measures. Multiple demographic, drug, and environmental correlates were controlled. Standardized, normative, reliable measures of fetal growth, intelligence quotient (IQ), behavior, executive function, and language were given at each age and risk for substance misuse assessed in adolescence. A subset of children received volumetric magnetic resonance imaging (MRI) at 7 years and functional MRI at 14 years. The effect of CE was determined through multiple regression analyses controlling for confounders.

RESULTS

Cocaine exposed had significant negative effects on fetal growth, attention, executive function, language, and behavior, while overall IQ was not affected. CE had significant negative effects on perceptual reasoning IQ and visual-motor skills and predicted lower volume of corpus callosum and decreased gray matter in the occipital and parietal lobes. CE children had higher risk for substance misuse. Confounding risk factors had additive effects on developmental outcomes.

CONCLUSIONS

Prenatal exposure to cocaine was related to poorer perceptual organization IQ, visual-spatial information processing, attention, language, executive function, and behavior regulation through early adolescence.

Preadolescent behavior problems after prenatal cocaine exposure: Relationship between teacher and caretaker ratings (Maternal Lifestyle Study)

BACKGROUND

We previously reported an association between prenatal cocaine exposure (PCE) and childhood behavior problems as observed by the parent or caretaker. However, these behavior problems may not manifest in a structured environment, such as a school setting.

OBJECTIVE

We determined whether there is an association between PCE and school behavior problems and whether ratings of behavior problems from the teacher differ from those noted by the parent or caretaker.

METHODS

The Maternal Lifestyle Study, a multicenter study, enrolled 1388 children with and without PCE at one month of age for longitudinal assessment. Teachers masked to prenatal drug exposure status completed the Teacher Report Form (TRF/6-18) when children were 7, 9, and 11 years old. We also administered the Child Behavior Checklist-parent report (CBCL) to the parent/caretaker at same ages and then at 13 years. We performed latent growth curve modeling to determine whether high PCE will predict externalizing, internalizing, total behavior, and attention problems at 7 years of age and whether changes in problems' scores over time differ between those exposed and non-exposed from both teacher and parent report. Besides levels of PCE as predictors, we controlled for the following covariates, namely: site, child characteristics (gender and other prenatal drug exposures), family level influences (maternal age, depression and psychological symptomatology, continuing drug use, exposure to domestic violence, home environment, and socioeconomic status), and community level factors (neighborhood and community violence).

RESULTS

The mean behavior problem T scores from the teacher report were significantly higher than ratings by the parent or caretaker. Latent growth curve modeling revealed a significant relationship between intercepts of problem T scores from teacher and parent ratings; i.e., children that were rated poorly by teachers were also rated poorly by their parent/caretaker or vice versa. After controlling for covariates, we found high PCE to be a significant predictor of higher externalizing behavior problem T scores from both parent and teacher report at 7 years (p=0.034 and p=0.021, respectively) in comparison to non-PCE children. These differences in scores from either teacher or caregiver were stable through subsequent years or did not change significantly over time. Boys had higher T scores than girls on internalizing and total problems by caretaker report; they also had significantly higher T scores for internalizing, total, and attention problems by teacher ratings; the difference was marginally significant for externalizing behavior (p=0.070). Caretaker postnatal use of tobacco, depression, and community violence were significant predictors of all behavior problems rated by parent/caretaker, while lower scores on the home environment predicted all behavior outcomes by the teacher report.

CONCLUSIONS

Children with high PCE are likely to manifest externalizing behavior problems; their behavior problem scores at 7 years from either report of teacher or parent remained higher than scores of non-exposed children on subsequent years. Screening and identification of behavior problems at earlier ages could make possible initiation of intervention, while considering the likely effects of other confounders.

The impact of antenatal cocaine use on maternal characteristics and neonatal outcomes

OBJECTIVE

To determine the risk factors and evaluate maternal and neonatal outcomes associated with antenatal cocaine use.

METHODS

This was a retrospective case-control study of 200 cocaine-exposed maternal-neonatal pairs and 200 controls from 1991 to 2000.

RESULTS

Cocaine-using mothers tended to be older, African American, multiparous and incarcerated and they utilized less prenatal care. However, 79% of Hispanics abusing cocaine were primarily English speaking. Cocaine use correlated with syphilis (36 vs. 1%, p = 0.000) and premature rupture of membranes (23 vs. 0%, p = 0.000), fetal demise (5 vs. 0%, p = 0.004), preterm delivery (40 vs. 6%, p = 0.000). Cocaine-exposed infants delivered earlier (36 vs. 39 weeks, p = 0.000), had lower birth weights (2660 vs. 3305 g, p = 0.000), more respiratory distress syndrome (14 vs. 4%, p = 0.001), congenital syphilis (12 vs. 1%, p = 0.000) and longer hospital stays (10 vs. 3 days, p = 0.000); 75% were placed in foster care or adoption and 37.5% had neonatal withdrawal syndrome. There was a stronger positive correlation between neonatal withdrawal and maternal urine toxicology (rho = 0.443, p = 0.000) than with neonatal urine screen (rho = 0.278, p = 0.003).

CONCLUSION

Cocaine use in pregnancy is associated with acculturation, lack of prenatal care, and significant social and obstetric complications resulting in increased neonatal morbidity secondary to prematurity, congenital infection and withdrawal syndrome.

Multifocal multi-organ ischaemia and infarction in a preterm baby due to maternal intravenous cocaine use: a case report

Introduction

Although the adverse effects of cocaine use in pregnancy are well recognised, we believe this case highlights the importance of considering the route of administration, and suggests the possibility of multifocal damage relating to intravenous use.

Case presentation

A Caucasian female baby of 29-weeks' gestation was spontaneously delivered and subsequently developed multi-organ failure considered unrelated to simple prematurity. Intensive care was re-orientated following the development of massive intraventricular haemorrhage.

Conclusion

This case illustrates the need for regular cranial ultrasound in babies of pregnancies at risk due to intravenous cocaine use and also the necessity of counselling women who misuse cocaine in the antenatal period. As such, this article will be of most interest to paediatric and obstetric staff.

Multifocal multi-organ ischaemia and infarction in a preterm baby due to maternal intravenous cocaine use: a case report

Introduction

Although the adverse effects of cocaine use in pregnancy are well recognised, we believe this case highlights the importance of considering the route of administration, and suggests the possibility of multifocal damage relating to intravenous use.

Case presentation

A Caucasian female baby of 29-weeks’ gestation was spontaneously delivered and subsequently developed multi-organ failure considered unrelated to simple prematurity. Intensive care was re-orientated following the development of massive intraventricular haemorrhage.

Conclusion

This case illustrates the need for regular cranial ultrasound in babies of pregnancies at risk due to intravenous cocaine use and also the necessity of counselling women who misuse cocaine in the antenatal period. As such, this article will be of most interest to paediatric and obstetric staff.

Biobehavioral Outcomes in Adolescents and Young Adults Prenatally Exposed to Cocaine: Evidence From Animal Models

Cocaine has been a popular illicit drug among drug-using pregnant women over the last three decades. Prenatal cocaine exposure (PCE) has significant effects on children's development throughout early childhood. Very few human studies, however, report the effects of PCE on adolescent or early-adult development. As knowledge about early childhood effects in human children was informed by animal studies, this review considers the effects of PCE on behavioral outcomes in adolescent and young adult animals and provides potential guidance for research in human children. Animal models prenatally exposed to cocaine manifest play deficits, decreased social interaction, and increased aggression during competition in adolescence and young adulthood. Altered behavioral adaptation after stress exposure, including hormonal response change, is also evident. Attention deficits are reported in adult offspring with PCE, not only in a novel environment, but also in a final task session, indicating effects of PCE on transition and maintenance of attention. Animal studies support that PCE effects may extend beyond early childhood and continue to adolescence and adulthood. Additionally, some studies highlight that behavioral changes in offspring with PCE born without teratogenesis remain latent and reveal themselves during adulthood when animals are under stress conditions. Based on the evidence from animal models, well-designed human studies are needed to elucidate the effects of PCE on older human children. Research models that combine behavioral measures with stressful challenges may hold potential in discerning a longer term influence of PCE.

Impact of prenatal cocaine exposure on child behavior problems through school age

OBJECTIVE

We examined the trajectory of childhood behavior problems after prenatal cocaine exposure.

METHODS

The Maternal Lifestyle Study, a longitudinal cohort study, enrolled children between 1993 and 1995 at 4 centers. Prenatal cocaine exposure was determined from mothers who admitted use and/or meconium results. Exposed children were matched with a group of nonexposed children within site and by gestational age, gender, race, and ethnicity. The study began at the 1-month corrected age with a total of 1388 children enrolled. A total of 1056 were assessed for internalizing, externalizing, and total behavior problems at ages 3, 5, and 7 years using the Child Behavior Checklist. Longitudinal hierarchical linear models were used to determine the effect of prenatal cocaine exposure on behavior problem trajectories while controlling for other prenatal exposures; time-varying covariates, including ongoing caregiver use of legal and illegal substances; demographic factors; family violence; and caregiver psychological distress.

RESULTS

High prenatal cocaine exposure was associated with the trajectory of internalizing, externalizing, and total behavior problems; these effects were independent of and less than the significant combined effect of prenatal and postnatal tobacco and alcohol exposures. Caregiver depression and family violence had independent negative influence on all behavior outcomes.

CONCLUSIONS

Prenatal cocaine exposure has a negative impact on the trajectories of childhood behavior outcomes. When they co-occur with prenatal cocaine exposure, prenatal and postnatal tobacco and alcohol exposures have added negative effects on behavior outcomes.

Fetal alcohol exposure impairs alveolar macrophage function via decreased glutathione availability

Immature function of the alveolar macrophage increases the risk of pulmonary infections in premature newborns. In utero alcohol increases fetal systemic oxidative stress. Because the premature lung is deficient in glutathione (GSH), we hypothesized that chronic in utero alcohol (ethanol) exposure exacerbates the oxidative stress within the developing lung, thereby impairing alveolar macrophage function. Additionally, we evaluated the effects of in vivo and in vitro GSH availability on ethanol-exposed macrophage function. Using a guinea pig model of chronic in utero ethanol exposure, fetal epithelial lining fluid (ELF) and alveolar macrophage GSH were decreased with increased markers of oxidative stress. Ethanol-exposed macrophage exhibited impaired phagocytosis and increased apoptosis compared with gestational control. When the GSH precursor S-adenosyl-methionine (SAM) was added to the maternal drinking water containing ethanol, fetal ELF and macrophage GSH were maintained and ELF oxidative stress diminished. In vivo maternal SAM therapy maintained macrophage phagocytosis and decreased apoptosis. In vitro GSH supplements also improved phagocytosis and viability in both premature and ethanol-exposed macrophage. This suggested that in utero ethanol impaired premature macrophage function and viability via decreased GSH availability. Furthermore, GSH supplementation during and after ethanol exposure improved fetal macrophage function and viability. These results add a new dimension to the detrimental effects of fetal alcohol exposure on the developing alveolar macrophage, raising the possibility of GSH therapy to augment premature alveolar macrophage function.

Prenatal cocaine exposure: a comparison of 2-year-old children in parental and nonparental care

Effects of prenatal cocaine exposure and parental versus nonparental care on outcome at 2 years of age were examined. The sample included 83 cocaine-exposed and 63 nonexposed children and their caregivers; 49 and 34 of the cocaine-exposed children experienced parental and nonparental care, respectively. Prenatal drug exposure was not related directly to children's outcome at 2 years of age. However, compared with cocaine-exposed children in parental care, those in nonparental care experienced a more optimal environment and performed better in several developmental domains at 2 years of age in spite of being at greater neonatal risk. Further analyses suggested that this protective effect of nonparental care was in part due to nonkin rather than kin care.

Fetal Alcohol and Drug Effects

BACKGROUND

Alcohol and drug use by pregnant women are harmful to the developing embryo and fetus. Teasing apart the specific contributions of each substance to adverse child outcome, however, proves difficult in practice. The risks to the neonate include intra-uterine growth retardation, birth defects, altered neurobehavior, and withdrawal symptoms. Subsequent behavior, development, and neurologic function may also be impaired.

REVIEW SUMMARY

Maternal cigarette smoking carries the greatest risk of impaired fetal growth of any of the substances discussed herein and has been linked to subsequent externalizing behaviors. Alcohol is a well-established teratogen. Heavy exposure to alcohol in a subset of infants is associated with fetal alcohol syndrome (FAS). Mental retardation is one of the main sequelae of alcohol exposure in utero. Fetal marijuana exposure has no consistent effect on outcome. Prenatal cocaine exposure has not been shown to have any detrimental effect on cognition, except as mediated through cocaine effects on head size. Although fetal cocaine exposure has been linked to numerous abnormalities in arousal, attention, and neurologic and neurophysiological function, most such effects appear to be self-limited and restricted to early infancy and childhood. Opiate exposure elicits a well-described withdrawal syndrome affecting central nervous, autonomic, and gastrointestinal systems, which is most severe among methadone-exposed infants.

CONCLUSION

Most adverse effects of prenatal drug exposure are self-limited, with catch-up growth and resolution of withdrawal and of prior neurobehavioral abnormalities noted over time. The exception is alcohol, which is linked to life-long impairments (i.e., mental retardation and microcephaly) and possibly cigarette-related behavioral effects. The absence of tangible evidence of detrimental long-term cocaine effects may reflect limitations in the methodology used to identify children at greatest risk for adverse outcome.

Cocaine and the critical care challenge

OBJECTIVE

Cocaine, which first made its appearance >1,000 yrs ago, is now widely used throughout the world. The physiologic responses to cocaine may cause severe pathologic effects. This review highlights the many critical care challenges resulting from these effects.

DESIGN

Historical vignettes, epidemiologic factors, modes of preparation and delivery, and the physiologic and pharmacologic effects of these agents are presented.

SETTING

Cocaine causes intense vasoconstriction, which potentially causes damage to all organ systems. Examples of these toxicities are presented.

PATIENTS

The adverse multisystem responses to cocaine exposure produce organ failure, which challenges diagnostic accuracy and therapeutic intervention. Organ system failure involves the brain, heart, lung, kidneys, gastrointestinal tract, musculature, and other organs. These harmful effects are additive to preexisting organ dysfunction.

INTERVENTION

Recognition of associated cocaine injury alerts the physician that organ dysfunction is more likely to occur and to be more severe. Such anticipation helps plan for therapy in the critical care setting.

RESULTS AND CONCLUSIONS

Cocaine use is an expanding health hazard, despite intense governmental efforts to contain its distribution and use. Recognition of the signs and symptoms of cocaine toxicity help anticipate the subsequent organ dysfunction and implement earlier organ system support.

Level of prenatal cocaine exposure and scores on the Bayley Scales of Infant Development: modifying effects of caregiver, early intervention, and birth weight

OBJECTIVES

The objectives of this study were 1) to assess whether there is an independent association between the level of prenatal cocaine exposure and infants' developmental test scores after control of potential confounding variables; and 2) if such an association exists, to determine which biological and social variables, individually and in interaction with each other, may modify it.

METHODS

In a prospective, longitudinal study of 203 urban term infants, 3 cocaine exposure groups were defined by maternal report and infant meconium assay: unexposed, heavier cocaine exposure (>75th percentile self-reported days of use or meconium benzoylecognine concentration), or lighter cocaine exposure (all others). Examiners, masked to exposure history, tested infants at 6, 12, and 24 months of age with the Bayley Scales of Infant Development.

RESULTS

The final mixed linear regression model included as fixed covariates level of prenatal exposure to cocaine, alcohol, and cigarettes; prenatal marijuana exposure; gestational age and birth weight z score for gestational age; and gender. Age at test, caregiver at time of each test (biological mother, kinship caregiver, unrelated foster caregiver), and any previous child-focused early intervention were included as time-dependent covariates. There were no significant adverse main effects of level of cocaine exposure on Mental Development Index (MDI), Psychomotor Development Index (PDI), or Infant Behavior Record. Child-focused early intervention interacted with level of cocaine exposure such that heavily exposed children who received such intervention showed higher adjusted mean MDI scores than all other groups. Although the sample was born at or near term, there was also a significant interaction of cocaine exposure and gestational age on MDI scores, with those in the heavier exposure group born at slightly lower gestational age having higher mean MDI scores compared with other children born at that gestational age. There was also a significant interaction on MDI between child's age and caregiver. At 6 months, the adjusted MDI of children living with a kinship caregiver was 15.5 points lower than that of children living with their biological mother, but this effect was diminished and was no longer significant at 24 months (difference in means: 4.3 points). The adjusted mean MDI of children in unrelated foster care at 6 months was 8.2 points lower than children of biological mothers, whereas it was 7.3 points higher at 24 months. Early intervention attenuated the age-related decline in PDI scores for all groups. Birth weight <10th percentile was associated with lower PDI scores for children with heavier cocaine exposure and with lower MDI scores for all groups.

CONCLUSIONS

Heavier prenatal cocaine exposure is not an independent risk factor for depressed scores on the Bayley Scales of Infant Development up to 24 months of age when term infants are compared with lighter exposed or unexposed infants of the same demographic background. Cocaine-exposed infants with birth weight below the 10th percentile for gestational age and gender and those placed with kinship caregivers are at increased risk for less optimal developmental outcomes. Pediatric clinicians should refer cocaine-exposed children to the child-focused developmental interventions available for all children at developmental risk.

Diastolic filling abnormalities by color kinesis in newborns exposed to intrauterine cocaine

Because cocaine crosses the placenta, we prospectively evaluated global and segmental systolic and diastolic cardiac function by color kinesis in clinically asymptomatic newborns who were exposed to cocaine in utero (group 1, n = 82). Their data were compared with normal controls (group 3, n = 87) and newborns exposed to drugs other than cocaine (group 2, n = 108). During left ventricular filling, newborns exposed to cocaine, compared with groups 2 and 3, had significantly (P <.05) higher global fractional area change (%) (76 +/- 10.3 vs 72 +/- 9.4 and 72 +/- 9.1, respectively), regional fractional area changes (%) for the anterior, septal, inferior, and lateral wall, and in the index of asynchrony (at 50% filling 13.2 +/- 5.8 vs 11.3 +/- 4.1 and 11.6 +/- 4.2, respectively). There were no significant differences in systolic function among the 3 groups. Prenatal cocaine exposure in asymptomatic infants leads to higher global and segmental fractional area changes and asynchrony during diastole. The significance and course of these alterations require further investigation.

Drugs of abuse in pregnancy

Care for the drug-using pregnant woman is being increasingly recognized as part of the obstetrician's role. There is great potential for improvement in provision of services for this group of women, partly because traditionally our antenatal clinics have not been perceived as being conducive to disclosure regarding drug use, but also because hard data and, indeed, randomized controlled trials on the subject, are scarce.From the little evidence available, and from our own experience in this area, we have attempted to outline the main problems encountered in the antenatal, intrapartum and postnatal periods with each of the main drugs of abuse and the management thereof. It is important to note that we include cigarette smoking and alcohol, probably the most commonly used drugs in pregnancy, and recognize that the picture is wider than the stereotypical emaciated intravenous heroin addict. Where possible, evidence from trial data is included, but much of the what is quoted is descriptive from personal experience from ourselves and others working in the field.

Heart rate variability in cocaine-exposed newborn infants

BACKGROUND

Infants born to cocaine-using mothers have a 3- to 8-fold increase in sudden infant death syndrome. Its underlying cause, in part, may be attributed to abnormal autonomic function. We proposed to study heart rate variability, reflecting autonomic control of the heart, in cocaine-exposed infants.

METHODS

From 1997 to 2000, we studied 217 asymptomatic, term infants, of whom 68 had intrauterine cocaine exposure (group I). Their data were compared with infants exposed to drugs other than cocaine (group II, n = 77) and no drugs (group III, n = 72). Twenty-four-hour heart rate variability was measured within 72 hours of birth.

RESULTS

Cocaine-exposed infants, as compared with the 2 control groups, had an overall significant decrease (P <.05) in global heart rate variability and a lower standard deviation of all valid N-N intervals in the recording (41.9 +/- 1.4 ms vs 47.6 +/- 1.3 ms and 46.9 +/- 1.3 ms, respectively). Vagal parameters such as high-frequency power and the square root of the mean of the squared differences between adjacent N-N intervals were also lower in newborns with heavy in utero cocaine exposure.

CONCLUSIONS

Decreased heart rate variability was seen in cocaine-exposed infants. Whether low heart rate variability is a marker for increased risk of sudden death in infants (as it is in adults with structural heart disease) is unknown and requires further investigation.

Developmental outcomes and environmental correlates of very low birthweight, cocaine-exposed infants

Fetal cocaine exposure may have differentially adverse effects on developmental outcomes of very low birthweight (VLBW) infants. As part of a longitudinal study, 31 cocaine-positive very low birthweight infants, and age, race and socioeconomic status matched VLBW controls enrolled at birth were followed. Neonatal maternal-child interactions, concurrent maternal psychological characteristics and environmental factors conceptualized as important for child outcome were assessed as well as standard developmental outcomes at 3 years. In the neonatal period, cocaine-exposed VLBW infants who remained in maternal custody tended to be rated as less responsive and their mothers as less nurturing, less emotionally available and with a tendency to use more maladaptive coping mechanisms than nonexposed VLBW infants. At follow-up, cocaine-exposed VLBW children were delayed in cognitive, motor and language development compared to controls. Almost half (45%) of the exposed children scored in the range of mental retardation compared to 16% of the comparison VLBW children. The persistent cognitive, motor and language delays of the cocaine-exposed VLBW children, combined with the poorer behavioral interactions of cocaine-using women with their infants in the neonatal period, indicate a need for increased developmental surveillance of cocaine-exposed VLBW infants with a focus on maternal drug treatment and parenting interventions.

Measuring prenatal drug exposure

Prenatal drug exposure is an important pediatric health issue. However, the effects on children are not clear because of limitations in the way drug exposure is typically measured. For example, one cannot say cocaine causes a specific outcome if cocaine exposure is not measured accurately. Before we can determine the developmental outcomes associated with drug exposure, 4 measurement issues must be considered: (1) the amount of exposure varies greatly, such as from 1 to 709 g of crack per month; (2) exposure may vary by trimester; (3) exposure could be to one drug or multiple drugs; and (4) different sources of exposure data can be inconsistent (e.g., toxicology and maternal self-report). We use data from 248 families participating in an ongoing longitudinal study to provide concrete examples of these measurement issues. Both nursing researchers and practitioners must carefully attend to measurement issues when interpreting research on the effects of prenatal drug exposure.

Fetal effects of cocaine: an updated meta-analysis

BACKGROUND

A very large number of women in the reproductive age group consume cocaine, leading to grave concerns regarding the long term health of millions of children after in utero exposure. The results of controlled studies have been contradictory, leading to confusion, and, possible, misinformation and misperception of teratogenic risk.

OBJECTIVE

To systematically review available data on pregnancy outcome when the mother consumed cocaine.

METHODS

A meta-analysis of all epidemiologic studies based on a priori criteria was conducted. Comparisons of adverse events in subgroups of exposed vs. unexposed children were performed. Analyses were based on several exposure groups: mainly cocaine, cocaine plus polydrug, polydrug but no cocaine, and drug free.

RESULTS

Thirty three studies met our inclusion criteria. For all end points of interest (rates of major malformations, low birth weight, prematurity, placental abruption, premature rupture of membrane [PROM], and mean birth weight, length and head circumference), cocaine-exposed infants had higher risks than children of women not exposed to any drug. However, most of these adverse effects were nullified when cocaine exposed children were compared to children exposed to polydrug but no cocaine. Only the risk of placental abruption and premature rupture of membranes were statistically associated with cocaine use itself.

CONCLUSIONS

Many of the perinatal adverse effects commonly attributed to cocaine may be caused by the multiple confounders that can occur in a cocaine using mother. Only the risk for placental abruption and PROM could be statistically related to cocaine. For other adverse effects, additional studies will be needed to ensure adequate statistical power.

Growth, development, and behavior in early childhood following prenatal cocaine exposure: a systematic review

CONTEXT

Despite recent studies that failed to show catastrophic effects of prenatal cocaine exposure, popular attitudes and public policies still reflect the belief that cocaine is a uniquely dangerous teratogen.

OBJECTIVE

To critically review outcomes in early childhood after prenatal cocaine exposure in 5 domains: physical growth; cognition; language skills; motor skills; and behavior, attention, affect, and neurophysiology.

DATA SOURCES

Search of MEDLINE and Psychological Abstracts from 1984 to October 2000.

STUDY SELECTION

Studies selected for detailed review (1) were published in a peer-reviewed English-language journal; (2) included a comparison group; (3) recruited samples prospectively in the perinatal period; (4) used masked assessment; and (5) did not include a substantial proportion of subjects exposed in utero to opiates, amphetamines, phencyclidine, or maternal human immunodeficiency virus infection.

DATA EXTRACTION

Thirty-six of 74 articles met criteria and were reviewed by 3 authors. Disagreements were resolved by consensus.

DATA SYNTHESIS

After controlling for confounders, there was no consistent negative association between prenatal cocaine exposure and physical growth, developmental test scores, or receptive or expressive language. Less optimal motor scores have been found up to age 7 months but not thereafter, and may reflect heavy tobacco exposure. No independent cocaine effects have been shown on standardized parent and teacher reports of child behavior scored by accepted criteria. Experimental paradigms and novel statistical manipulations of standard instruments suggest an association between prenatal cocaine exposure and decreased attentiveness and emotional expressivity, as well as differences on neurophysiologic and attentional/affective findings.

CONCLUSIONS

Among children aged 6 years or younger, there is no convincing evidence that prenatal cocaine exposure is associated with developmental toxic effects that are different in severity, scope, or kind from the sequelae of multiple other risk factors. Many findings once thought to be specific effects of in utero cocaine exposure are correlated with other factors, including prenatal exposure to tobacco, marijuana, or alcohol, and the quality of the child's environment. Further replication is required of preliminary neurologic findings.

Brain proton magnetic resonance spectroscopy and imaging in children exposed to cocaine in utero

OBJECTIVE

The effects of prenatal cocaine exposure have been examined using neurobehavioral and brain structural evaluations; however, no study has examined the effects of prenatal cocaine on brain metabolism. Proton magnetic resonance spectroscopy ((1)H-MRS) is a noninvasive method to examine the biochemistry of various brain regions. The purpose of this study was to examine the possible neurotoxic effects of prenatal cocaine exposure on the developing brain using (1)H-MRS.

METHODS

Cocaine-exposed children (n = 14) and age-matched unexposed control participants (n = 12) were evaluated with MRI and localized (1)H-MRS. Metabolite concentrations of N-acetyl-containing compounds (NA), total creatine (Cr), choline-containing compounds, myoinositol, and glutamate + glutamine were measured in the frontal white matter and striatum.

RESULTS

Despite an absence of structural abnormalities in either group, children exposed to cocaine in utero had significantly higher Cr (+13%) in the frontal white matter. NA, primarily a measure of N-acetyl aspartate and neuronal content, was normal in both regions examined by (1)H-MRS. Normal NA suggests no significant neuronal loss or damage in the 2 brain regions examined in children exposed to cocaine prenatally.

CONCLUSIONS

Consistent with findings in abstinent adult cocaine users, we found increased Cr in the frontal white matter, with normal NA in children exposed to cocaine. These findings suggest the need to investigate further possible abnormalities of energy metabolism in the brain of children exposed to cocaine in utero. In addition, this study demonstrates the feasibility of using (1)H-MRS to investigate the effects of prenatal drug exposure on the developing brain.

Late embryonic ritanserin exposure fails to alter normal responses to immune system stimulation in young chicks

Prior studies in our laboratory have demonstrated that prenatal treatment with the serotonin2 (5-HT2) antagonist ritanserin is effective in blocking some of the lethal, dysmorphic, cardiovascular, and behavioral consequences of excessive direct or indirect stimulation of 5-HT2 receptors in the developing chicken. The efficacious dose range for ritanserin in these studies had very little or no effect on the above measures of toxicity when administered alone. In the present study, we extend our characterization of ritanserin's potential toxicity, or lack thereof, to include the normal behavioral and endocrine responses to immune system stimulation by the endotoxin lipopolysaccharide (LPS). LPS administration induces a syndrome collectively known as sickness behavior, manifest as altered thermoregulatory processes leading to fever, and increased serum concentrations of neuroendocrine hormones, including corticosterone. These survival-promoting responses to LPS were assessed in young chickens that had been treated with doses of ritanserin ranging from 0 to 2.7 mg/kg on embryonic day 17 (E17). When sickness behavior was assessed in 5-7-day-old chicks 1 h post-LPS injection, E17 ritanserin-treated subjects did not differ from controls. At 4-6 h post-LPS, 4-day-old chicks displayed a robust fever, and E17 ritanserin did not affect the magnitude of this response. Similarly, E17 ritanserin treatment failed to affect corticosterone concentrations 2 h post-LPS in 14-day-old chicks. Thus, ritanserin treatment during late embryogenesis, a time when it is effective against direct and indirect acting 5-HT2 agonists, failed to modify the survival promoting and beneficial interactions between the nervous, endocrine, and immune systems that are elicited following immunostimulation.

NEONATAL VISUAL INFORMATION PROCESSING IN COCAINE-EXPOSED AND NON-EXPOSED INFANTS

This study investigated early neonatal visual preferences in 267 poly drug exposed neonates (131 cocaine-exposed and 136 non-cocaine exposed) whose drug exposure was documented through interviews and urine and meconium drug screens. Infants were given four visual recognition memory tasks comparing looking time to familiarized stimuli of lattices and rectangular shapes to novel stimuli of a schematic face and curved hourglass and bull's eye forms. Cocaine-exposed infants performed more poorly, after consideration of confounding factors, with a relationship of severity of cocaine exposure to lower novelty score found for both self-report and biologic measures of exposure, Findings support theories which link prenatal cocaine exposure to deficits in information processing entailing attentional and arousal organizational systems. Neonatal visual discrimination and attention tasks should be further explored as potentially sensitive behavioral indicators of teratologic effects.

Open-field and LPS-induced sickness behavior in young chickens: effects of embryonic cocaine and/or ritanserin

Exposure to drugs of abuse during embryogenesis may adversely affect nervous, immune, and endocrine systems development. We compared exposure on embryonic day 18 (E18) by single or multiple cocaine (COC) injections (56.25 mg/kg total dose for both) or saline on hatching and activity measures. In saline-exposed controls, repeated testing, age, and gender affected activity levels. A single or multiple COC injections increased the median latency to explore and multiple COC injections decreased the median number of lines crossed by female chicks in the open field. We also determined if pretreatment with the serotonin2 (5-HT2) receptor antagonist ritanserin could attenuate COC's effects on open-field behavior as well as behaviors sensitive to immune system stimulation (lipopolysaccharide (LPS)-induced sickness behavior). Eggs containing embryos were pretreated on E17 with 0.4 mg ritanserin/kg or its vehicle followed by multiple COC injections or saline on E18. E18 COC treatment decreased the median number of lines crossed and distress vocalizations in females. Ritanserin pretreatment mitigated the COC induced effects. E18 COC exposure also suppressed LPS-induced sickness behaviors in both males and females, increasing food consumption and the time spent awake and active, as well as decreasing the time spent sleeping. Ritanserin alone had no effect on the food consumed or time spent active, nor did this dose affect COC-induced alterations in sickness behavior. Ritanserin alone decreased time spent sleeping and also failed to affect the COC-induced suppression. Thus, embryonic COC exposure can suppress open field and LPS-induced sickness behavior in the young chick, and ritanserin pretreatment can block the former, but not the latter effects at the dose chosen for these experiments.

Neonatal neurobehavioral and neuroanatomic correlates of prenatal cocaine exposure. Problems of dose and confounding

Complex methodologic challenges face researchers studying the effects of prenatal cocaine exposure on infant outcome. These include unavoidable imprecision in ascertaining the gestational timing and dose of cocaine to which the fetus was exposed and difficulties in identifying and quantifying the confounding, mediating, and moderating variables. Review of research on neonatal behavioral and cranial ultrasound findings following in utero cocaine exposure is used to illustrate these issues. We conclude that there are measurable but not dramatic dose-related effects of prenatal cocaine exposure on infant central nervous system structure and function. The effects of dose of prenatal cocaine exposure on later child development remain to be determined. Such research would be facilitated by a scientific consensus delineating relative doses of prenatal cocaine exposure.

Cocaine in pregnancy. Recent data on maternal and fetal risks

Cocaine continues to be abused during pregnancy, creating increased demands on the health care system. Epidemiology and basic science research have identified and confirmed risks of adverse maternal and fetal effects when cocaine is used during pregnancy. These effects of cocaine in pregnant women often are influenced by a number of confounding variables. This article reviews those cocaine effects as well as recent data, which examine in greater detail the risks of adverse outcomes of prenatal cocaine exposure during pregnancy.

Incidence and description of structural brain abnormalities in newborns exposed to cocaine

OBJECTIVE

This study was undertaken to determine whether an increased incidence of structural brain abnormalities could be demonstrated in newborns exposed to cocaine.

STUDY DESIGN

This study was part of a prospective, longitudinal study of 154 cocaine users matched to 154 control subjects on prenatal risk level, race, parity, and socioeconomic status. Subjects were enrolled prenatally from a rural public health department population or at delivery. Drug exposure was determined by means of repeated, detailed histories and urine screening for drug metabolites. Ultrasonographic examinations were performed within 4 days of birth by experienced technologists and were read by one experienced radiologist, each blinded to drug use history.

RESULTS

Cranial ultrasonography results were available for 266 infants (134 cocaine-exposed; 132 control). Only 27 infants had ultrasonography results that were not considered normal, and there were no significant differences between groups (17 cocaine-exposed vs 10 control; p = 0.119). Identified abnormalities included choroid plexus cysts, subependymal cysts, mildly dilated ventricles, and a cyst of the third ventricle.

CONCLUSIONS

The incidence of abnormal cranial ultrasonography results in our cocaine-exposed group was lower than that previously reported in the literature and not significantly different from the control group. In addition, the identified lesions were less severe than previously reported, despite a wide range of cocaine use in our sample, including heavy use.

Prenatal cocaine exposure produces gender-specific motor effects in aged rats

This investigation employed a longitudinal analysis of a complex motor skill in rats that were exposed prenatally to cocaine. Offspring were derived from four maternal treatment groups: 50 mg/kg cocaine, their pair-fed controls, 25 mg/kg cocaine, and freely fed controls. Cocaine was administered via gavage from gestation day 6-20. A maternal fostering procedure was used. Pairs of male and female littermates began training when 9, 13, or 19 months old. The behavioral procedure involved fixed-ratio (FR) lever pressing to obtain brief periods of wheel running. The oldest males from the 50 mg/kg, 25 mg/kg, and pair-fed groups performed significantly fewer wheel revolutions per opportunity than females or freely fed males. In general, animals earned fewer opportunities to run as the FR requirement was increased over sessions. However, within each age-by-gender group, subjects from the four treatment groups performed equivalent amounts of lever pressing. The specific effect on the motor aspect of the procedure may have resulted from a reduction of motor coordination, balance, or strength, or a diminished capacity of wheel running to serve as a reinforcing stimulus in a cocaine-sensitive subgroup.

SENSORIMOTOR DEVELOPMENT IN COCAINE-EXPOSED INFANTS

This study investigated effects of prenatal cocaine exposure on infant sensorimotor development. One hundred and sixty-seven 12-month-olds (74 cocaine-exposed and 93 unexposed) were assessed using the Bayley Scales of Infant Development (BSID). Ninety-seven had previously been evaluated on the Movement Assessment of Infants and the Test of Sensory Functions in Infants at age 4 months. On the BSID, the cocaine-exposed infants performed less well on the Mental portion and were more frequently rated as behaviorally suspect. Cocaine-exposed infants also performed less well at four months on the motor and sensory measures. Early motor performance predicted 12 month BSID mental, motor and behavioral outcomes. Cocaine exposure had an effect independent from confounders on general cognitive and specific motor and behavioral outcomes.

Cocaine: pathophysiology and clinical toxicology

PURPOSE

To review the medical complications of cocaine abuse and the mechanisms of action of cocaine that contribute to medical complications.

DATA SOURCES

Pertinent articles identified through a MEDLINE search of the English-language literature from 1985 to 1996 and through a manual search of bibliographies of all identified articles.

STUDY SELECTION

All articles describing complications of cocaine use including case reports, small reported series, and review articles.

DATA SYNTHESIS

A qualitative description of reported complications.

RESULTS

Since the introduction of freebase and crack cocaine, multiple medical complications have been observed, and all major body organ systems have been affected. Cocaine can cause acute strokes, myocardial infarction, cardiac dysrhythmias, pulmonary edema, rhabdomyolysis, and acute renal failure.

CONCLUSION

Adverse reactions to cocaine should be considered in the differential diagnosis of acute ischemic events that occur in young adults. General awareness of the significant complications of cocaine will facilitate early diagnosis and prompt treatment.

Perinatal substance abuse: the impact of reporting infants to child protective services

OBJECTIVE

The purposes of this study were to follow the judicial placement of newborns with positive toxicology screening results and to determine how long such infants remained in foster care, separated from their mothers or other relatives, and the length of court dependency. We also determined the mothers' compliance with court orders, the availability and use of rehabilitative services, factors used by the court to determine the final disposition, and the eventual placement of the infants.

METHODS

The cohort sample consisted of all infants from San Mateo County (CA) born at Stanford University Hospital during a 2-year period whose urine tests in the well-baby nursery were positive for illicit substances. Fifty-three newborns were identified, and their medical records and court documents were matched and reviewed from birth until termination of judicial review (or 5 years). Data were summarized and analyzed by logistic regressions to identify predictors of specific outcomes.

RESULTS

All 53 infants had normal physical examinations and uneventful hospital courses. Their ethnic distribution, with 68% being African-American and 7% being Hispanic, differed from the rest of the nursery population, which was predominantly Hispanic. Twenty-six (46%) of the 53 infants were returned to their mothers within 1 week of birth; 39 (76%) of the infants were reunited with some relative within the first month of life. At 12 months of age, 10 infants (19%) remained in foster care; however, none remained in foster care beyond 18 months. The length of time infants were dependents of the court ranged from 1 month to >5 years; 70% of the cases were "closed" between 6 and 30 months of life. Nine (17%) were dependents of the court for >36 months. Final placement of the infants was 35 (66%) reunited with at least one parent, 9 (17%) in long-term guardianship relationships with other relatives, and 9 (17%) adopted. All of the mothers were ordered to complete a drug rehabilitation program; 24 mothers (44%) fully complied and had repeatedly drug-free urine tests; 2 others (4%) had drug-free urine tests after incomplete participation in drug rehabilitation. Twenty-two (42%) of the mothers never complied with drug rehabilitation. Subsequent drug use was evident in less than half of the mothers during the period of study. Only one mother was reported for child abuse. Characteristics that most strongly predicted failure in family reunification were a history of failed drug rehabilitation, previous involvement of Child Protective Services, or previous removal of a child because of substance abuse.

CONCLUSION

Identifying and reporting newborns exposed to maternal substance abuse during pregnancy can be associated with beneficial changes in the environment of the infants and successful rehabilitation of many mothers. The use of judicial supervision, rehabilitative and supportive services, and long-term involvement of social services without criminal prosecution are key to successful outcome. This study supports the policy and recommendation of the American Academy of Pediatrics and should lessen health professionals' concerns about negative effects of reporting these patients to Child Protective Services.

Medical and Psychologic Risks of Maternal Cocaine Use

The growing use of crack-cocaine by women of child-bearing age poses significant management problems for physicians. Both animal and human studies suggest that cocaine exerts significant negative effects on maternal health, the course of pregnancy, and infant developmental outcome. Maternal pregnancy complications and increased rates of low birth weight and prematurity in infants who are fetally exposed are well documented. However, available studies of neurobehavioral outcomes for cocaine-exposed infants are still inconclusive. Physicians need to become knowledgeable about the potential effects of maternal drug addiction during pregnancy to provide appropriate medical care.

[Consequences of cocaine addiction during pregnancy on the development in the child]

Cocaine facilitates neurotransmitter release from the central nervous system, decreases their re-uptake at the synapse junction level and increases their blood level due to receptors blockade. During pregnancy cocaine inhibits uterine adrenergic beta receptors and easily crosses the placenta, the main obstetrical consequences of overstimulation of the noradrenergic system being miscarriage, retroplacental haematoma, ruptured uterus, short and premature labour. Fetal and neonatal consequences resulting from both a decreased uterine blood flow and a direct effect of cocaine on fetal development can be severe. Decreased uterine blood flow lowers oxygen and nutriment transport which in turn can induce intra-uterine growth retardation. The direct effect of cocaine on the fetus is responsible for an increased catecholamine plasma concentration leading to vasoconstriction episodes, increased heart rate and blood pressure, and subsequent oxygen requirement. Several malformations have been reported, sometimes severe (involving central nervous system, heart, digestive tract, urinary tract and bone) that are mainly due to fetal circulation failure. Cocaine can also directly alter brain development because of neuronal mistargeting within the cerebral cortex.

Data Base of Studies on Prenatal Cocaine Exposure and Child Outcome

A computerized data base of characteristics and findings of the literature on prenatal exposure and child outcome was developed. The data base can be used to summarize and describe the literature resulting in a more objective understanding of the findings as well as to determine methodological problems that can shape the direction of future studies. Based on a literature search 99 studies were identified, 76 of which met methodological criteria and were included in the final data base. The data base shows that our knowledge base is limited, scattered, and compromised by methodological problems that mitigate any conclusions about whether or not or how prenatal cocaine exposure affects child outcome. Only a few studies have followed children beyond age 3. In addition, the cocaine problem is more complicated than first envisioned. It is a multifactorial problem including the use of other drugs and parenting and environmental lifestyle issues.

Outcome, cost analysis, and long-term follow-up in preterm infants with massive grade IV germinal matrix hemorrhage and progressive hydrocephalus

OBJECTIVE

The benefit of aggressive management and surgical intervention in preterm infants with massive Grade IV intracranial hemorrhage has been questioned based on the poor outcome of this group of patients despite such therapy. To further delineate this problem, we reviewed the records of premature neonates in this category as to outcome and initial hospital cost.

METHODS

We performed a retrospective review of the medical records at our institution from 1977 to 1987 to identify premature neonates who had sustained massive hemorrhagic infarction of one hemisphere in addition to having blood in both ventricles and progressive hydrocephalus.

RESULTS

During the study, a total of 52 such patients were identified, only 19 (6 female and 13 male patients) of whom survived. Intellectual function was observed to be greater than 2 standard deviations below the mean in 15 of the 19 patients, between 1 and 2 standard deviations below the mean in 1 of 19, and 1 standard deviation below the mean in 3 of 19. Motor function was as follows: 12 of 19 had marked spastic quadriparesis, 2 of 19 had moderate spastic quadriparesis, 3 of 19 had spastic hemiplegia, 1 of 19 had spastic diplegia, and 1 of 19 had mild spastic hemiparesis. Eleven of 19 had chronic seizure disorders. The first hospitalization cost for the group of patients exceeded, on the average, $150,000 per patient for the 19 long-term survivors.

CONCLUSION

As we have previously reported, logistic regression analysis determined that grade of hemorrhage was the only significant predictor of cognitive and motor outcomes. Most premature neonates with massive intracranial hemorrhages do not survive. The outcomes in those who do is very poor and the cost so high that we suggest that until therapeutic intervention exhibits efficacy, the consideration of withdrawal of life support should be presented as an option to the parents of these unfortunate children.

Relationship of prenatal cocaine exposure and maternal postpartum psychological distress to child developmental outcome

Maternal cocaine use during pregnancy can affect the infant directly through toxic effects or indirectly through cocaine's influence on maternal psychological status. We followed 160 cocaine exposed and 56 nonexposed infants and their mothers identified at birth through interview and/or urine screen. Although cocaine exposure defined the groups, infant exposure to alcohol, marijuana, and tobacco was allowed to vary. Infants were 99% African American and poor. All mothers completed the Brief Symptom Inventory (BSI) and infants were given the Bayley Scales of Mental (MDI) and Motor (PDI) Development at a mean corrected age of 17 +/- 8 months. Both MDIs (94 +/- 17 vs. 103 +/- 16) and PDIs (101 +/- 16 vs. 108 +/- 12) were lower for cocaine exposed infants. Psychological distress was greater in cocaine using mothers. Hierarchical multiple regression was used to assess the relative effects of gestational age, maternal psychological distress, and cocaine and polydrug exposure on infant outcomes. Both psychological distress and cocaine and alcohol exposure predicted lower MDIs after controlling for prematurity. Neither psychological distress nor alcohol exposure predicted motor outcome, while cocaine had a significant effect. Tobacco and marijuana exposure were unrelated to outcome. These findings provide further support for direct effects of cocaine and alcohol on infant development as well as highlight the need for studies to document maternal psychological factors, which may increase child risk for poorer outcomes.

Standardized test performance of children with a history of prenatal exposure to multiple drugs/cocaine

Twenty-four children, age 14 to 50 months, with a history of prenatal exposure to multiple drugs including cocaine, were matched by adjusted birth age and sex to 24 children with no history of drug exposure. All children had been living in stable, drug-free environments from at least the age of 11 months. Tests administered included the Sequenced Inventory of Communicative Development-Revised (SICD), the Bayley Scales of Infant Development, and the Peabody Picture Vocabulary Test-Revised (PPVT-R). Results indicated significant differences between groups and genders on the SICD when age was covaried and between groups on the Bayley. No groups or genders differed on the PPVT-R. Many (45.8%) of the children in the drug-exposed group qualified for intervention services according to Washington state criteria. Subject characteristics, other than age, did not play a significant role in the findings of group differences. It is concluded that, due to the cumulative effects of prenatal history, these children should be considered at risk for language delay.

New evidence for neurobehavioral effects of in utero cocaine exposure

Most studies of prenatal cocaine exposure have found gestational age or intrauterine growth deficits but few, if any, cognitive effects. In a large, well-controlled study we detected cognitive deficits in relation to heavy cocaine exposure. These findings demonstrate that prenatal exposure to cocaine at sufficiently high doses early in pregnancy has the potential to produce cognitive changes in infants and that more focused, narrow-band tests may be necessary to detect these subtle neurobehavioral effects. A total of 464 inner-city, black infants whose mothers were recruited prenatally on the basis of pregnancy alcohol and cocaine use were tested at 6.5, 12, and 13 months of age. Standard analyses, based on presence or absence of cocaine use during pregnancy, confirmed effects on gestational age but failed to detect cognitive effects. A new approach to identifying heavy users found that heavy exposure early in pregnancy was related to faster responsiveness on an infant visual expectancy test but to poorer recognition memory and information processing, deficits consistent with prior human and animal findings. These persistent neurobehavioral effects of heavy prenatal cocaine exposure appear to be direct effects of exposure and independent of effects on gestational age.

Prenatal cocaine exposure effects on arousal-modulated attention during the neonatal period

The organization of arousal and attention as a function of intrauterine cocaine exposure was investigated in 180 normal nursery infants prior to hospital discharge and at 1 month of age. This was done by studying visual looking preferences when infants were in three arousal conditions: less aroused (after feeding); more aroused-endogenous (before feeding); and more aroused-exogenous (after feeding but including 8-Hz visual stimulation prior to each visual preference trial). The stimuli were light panels illuminated at three temporal frequencies between 1 and 8 Hz presented in pairs using a balanced presentation series of trials. Infants not exposed to cocaine demonstrated strong arousal-modulated attention, preferring faster frequencies when less aroused and slower frequencies when more aroused in both endogenous and exogenous conditions. In contrast, cocaine-exposed infants showed a lack of arousal-modulated attention and preferred faster frequencies of stimulation regardless of arousal condition. Similar differences in arousal-modulated attention as a function of cocaine exposure were obtained at 1 month after birth, indicating that these effects lasted longer than would be reasonable to attribute to the active presence of cocaine or its metabolites. This form of stimulus-seeking behavior was shown to be independent of confounding factors associated with prenatal cocaine exposure such as the absence of prenatal care, alcohol use, minority status, or gender, as well as mediating factors associated with growth such as birthweight. A direct and more chronic effect of intrauterine cocaine exposure on arousal-modulated attention and presumably on the developing CNS therefore was supported.

Postnatal development of the dopamine transporter: a quantitative autoradiographic study

The dopamine transporter performs an important role in regulating neurochemical transmission at dopaminergic synapses, as well as dopamine synthetic activity in dopaminergic neurons. Certain drugs and toxins exert effects at the transporter, especially cocaine, a common drug of abuse. We studied the development of these sites in the rat at postnatal ages day 0, 5, 10, 15, 21 and adult using quantitative autoradiography with the cocaine analogue [125I]RTI-55. At birth, certain structures such as the substantia nigra, interstitial nucleus of the medial longitudinal fasciculus, frontal and parietal cortex, and substantia inominata had [125I]RTI-55 binding levels that were already near the adult value. The striatum developed later, showing earlier growth in the anterior and dorsolateral regions, with early localization in both striosomes and a subcallosal streak. Anterior-to-posterior and lateral-to-medial gradients were present at day 0. The anterior striatum, ventral tegmental region, substantia nigra compacta and bed nucleus of the stria terminal is showed transient peaks in binding levels that were higher than the adult values. Structures showing relatively late development included the prefrontal cortex, nucleus accumbens shell, olfactory tubercle and subthalamic nucleus. Knowledge of the differential developmental patterns of the dopamine transporter in different brain regions may have implications for understanding the neurodevelopmental effects of prenatal cocaine exposure.

The impact of prenatal cocaine exposure: studies of the developing infant

This article traces several major phases of research evaluating the development of infants exposed to cocaine. Although initial studies focused on the medical neurobehavioral status of the neonate, these studies often lacked appropriate comparison groups, attention to polydrug use, and follow-up after hospital discharge. As studies began to include longer follow-up periods and the types of comparison groups necessary to evaluate the unique effects of cocaine versus factors such as poverty and polydrug use, the deleterious effects of cocaine exposure were not as apparent. Although most early studies focused only on mental and motor outcomes, recent studies evaluating learning processes, emotional development, and the effects of cocaine-exposed infants' unique caretaking environments may provide more detailed descriptions of the outcomes of this growing population. This article discusses numerous methodological issues that continue to challenge this complex research area and recent research efforts that may prove beneficial in guiding future studies.