Prenatal Cocaine Exposure and Motor Performance at 4 Months

Associations of Maternal Prenatal Drug Abuse With Measures of Newborn Brain Structure, Tissue Organization, and Metabolite Concentrations

IMPORTANCE

Increasing rates of illicit drug use during pregnancy may be associated with risk for long-term health problems in prenatally exposed children.

OBJECTIVE

To identify the associations of prenatal exposure to illicit drugs with organization of the newborn brain.

DESIGN, SETTING, AND PARTICIPANTS

For this cohort study, a volunteer sample of 210 illicit drug-using and nonusing mothers and their newborns was enrolled from prenatal clinics and drug abuse treatment programs in New York, New York. Enrollment, scanning, and long-term follow-up occurred from September 2004 through February 2012, and image processing and statistical analyses continued through fall 2018. In addition to 26 participants with incomplete data, a total of 64 mothers were lost to follow-up during pregnancy, and 13 newborns were lost to follow-up at birth because of perinatal complications.

EXPOSURES

Newborns were assigned to 1 of 4 primary exposure groups based on the history of most frequent maternal drug use: marijuana, cocaine, methadone maintenance, and/or heroin. Unexposed newborns were controls.

MAIN OUTCOMES AND MEASURES

Unsedated magnetic resonance imaging (MRI) of newborn brains was performed shortly after birth. Infant neurodevelopmental outcomes were assessed at age 12 months. MRI modalities included anatomical imaging, diffusion tensor imaging, T2 relaxometry, and magnetic resonance spectroscopic imaging. Infant neurodevelopmental outcomes included Bayley scales of infant development-III and Vineland Adaptive Behavior Scales. Statistical analyses were performed with results represented on the brain images.

RESULTS

Of 118 mothers, 42 (35%) were in the control group (mean [SD] age, 25.9 [6.1] years), 29 (25%) were in the cocaine group (mean [SD] age, 29.0 [6.1] years), 29 (25%) were in the marijuana group (mean [SD] age, 24.3 [5.5] years), and 18 (15%) were in the methadone and/or heroin group (mean [SD] age, 30.9 [5.7] years). Not all newborns could be scanned successfully; therefore, usable MRIs were acquired for 118 newborns from predominantly minority groups and with economically disadvantaged mothers. Anatomic abnormalities were detected in similar locations across all 3 drug exposures and included smaller volumes in the dorsal, medial, and ventral surfaces of the frontal lobe and dose-related increases in volumes in the lateral temporal lobe, dorsal parietal lobe, and superior frontal gyrus. Dose-related increases in diffusion tensor measures of tissue organization, decreases in T2 relaxometry times, and increases in spectroscopy metabolite concentrations were similar across exposures. These associations of exposures with brain measures were similar to the associations of newborn age with brain measures. The anatomic and diffusion tensor imaging measures suppressively mediated the associations of prenatal exposure with poorer 12-month infant outcomes.

CONCLUSIONS AND RELEVANCE

The findings suggest that prenatal drug exposure is associated with measures of newborn brain tissue in patterns that may indicate that exposures accelerated normal fetal brain maturation, which in turn mediated the associations with poorer 12-month infant outcomes.

The Association Between Antenatal Maternal Self-reported Substance Use, Maternal Characteristics, and Obstetrical Variables

BACKGROUND

Substance use disorders during pregnancy are a concern both to the public and medical community, because the negative consequences can be detrimental to both mother and the fetus. The accurate identification of prenatal drug exposure is necessary to determine appropriate medical and psychosocial intervention, and to identify risk factors that may affect outcomes for the mother and her newborn. The prevalence of prenatal drug exposure is very difficult to estimate because of flaws in all methods of identification.

OBJECTIVE

The study is designed to identify risk factors and demographic variables that contribute to nondisclosure of illicit and nonillicit substance use. In addition, this study aims to determine if nondisclosure leads to adverse neonatal outcomes.

STUDY DESIGN

Newborns delivered with a positive meconium or urine toxicology, and/or known maternal exposure to illicit and nonillicit substances, were identified. Maternal records were reviewed for disclosure of substance use during pregnancy at admission for delivery along with other medical and demographic variables. Women with antenatal prescription drug use that may alter toxicology screens were excluded from analysis. Pediatric records were also reviewed to obtain neonatal variables.

RESULTS

One hundred sixty-eight newborns were identified as having prenatal exposure to an illicit or nonillicit substance over the 4-year period. Eighty-six per cent (145/168) of women tested positive or their newborn tested positive for at least 1 illicit substance, and 49% (82/168) tested positive for multiple illicit substances. Fifty-four per cent (91/168) of women did not disclose using at least one illicit drug for which she or her newborn tested positive.With regards to maternal characteristics, there was no statistically significant difference between age (P = 0.958), parity (P = 0.300), or race (P = 0.531), and disclosure or failure to disclose about illicit drug use. However, patients who did not report prenatal illicit drug use (33/82 = 40%) were less likely (P = 0.049) to receive complete prenatal care (defined as 3 or more visits) compared with those who acknowledged their substance use (40/70 = 57%).

CONCLUSION

Substance use disorders during pregnancy are an often underestimated cause of maternal, fetal, and neonatal complications. Limited studies have examined the relationship between maternal characteristics and associated illicit or nonillicit drug use. The absence of correlation between maternal demographics and disclosure of illicit substance use demonstrates the fact that all antepartum patients are at risk for these behaviors. Furthermore, the fact that women who did not disclose their illicit drug use were less likely to seek complete prenatal care reflects the need for physicians to provide a destigmatized healthcare environment, encouraging pregnant women to disclose their substance use so they can be provided with appropriate counseling and treatment.

Prenatal cocaine exposure and its impact on cognitive functions of offspring: a pathophysiological insight

It is estimated that approximately 0.5%-3% of fetuses are prenatally exposed to cocaine (COC). The neurodevelopmental implications of this exposure are numerous and include motor skill impairments, alterations of social function, predisposition to anxiety, and memory function and attention deficits; these implications are commonly observed in experimental studies and ultimately affect both learning and IQ. According to previous studies, the clinical manifestations of prenatal COC exposure seem to persist at least until adolescence. The pathophysiological cellular processes that underlie these impairments include dysfunctional myelination, disrupted dendritic architecture, and synaptic alterations. On a molecular level, various neurotransmitters such as serotonin, dopamine, catecholamines, and γ-aminobutyric acid seem to participate in this process. Finally, prenatal COC abuse has been also associated with functional changes in the hormones of the hypothalamic-pituitary-adrenal axis that mediate neuroendocrine responses. The purpose of this review is to summarize the neurodevelopmental consequences of prenatal COC abuse, to describe the pathophysiological pathways that underlie these consequences, and to provide implications for future research in the field.

Psychostimulants and movement disorders

Psychostimulants are a diverse group of substances with their main psychomotor effects resembling those of amphetamine, methamphetamine, cocaine, or cathinone. Due to their potential as drugs of abuse, recreational use of most of these substances is illegal since 1971 Convention on Psychotropic Substances. In recent years, new psychoactive substances have emerged mainly as synthetic cathinones with new molecules frequently complementing the list. Psychostimulant related movement disorders are a known entity often seen in emergency rooms around the world. These admissions are becoming more frequent as are fatalities associated with drug abuse. Still the legal constraints of the novel synthetic molecules are bypassed. At the same time, chronic and permanent movement disorders are much less frequently encountered. These disorders frequently manifest as a combination of movement disorders. The more common symptoms include agitation, tremor, hyperkinetic and stereotypical movements, cognitive impairment, and also hyperthermia and cardiovascular dysfunction. The pathophysiological mechanisms behind the clinical manifestations have been researched for decades. The common denominator is the monoaminergic signaling. Dopamine has received the most attention but further research has demonstrated involvement of other pathways. Common mechanisms linking psychostimulant use and several movement disorders exist.

Developmental consequences of fetal exposure to drugs: what we know and what we still must learn

Most drugs of abuse easily cross the placenta and can affect fetal brain development. In utero exposures to drugs thus can have long-lasting implications for brain structure and function. These effects on the developing nervous system, before homeostatic regulatory mechanisms are properly calibrated, often differ from their effects on mature systems. In this review, we describe current knowledge on how alcohol, nicotine, cocaine, amphetamine, Ecstasy, and opiates (among other drugs) produce alterations in neurodevelopmental trajectory. We focus both on animal models and available clinical and imaging data from cross-sectional and longitudinal human studies. Early studies of fetal exposures focused on classic teratological methods that are insufficient for revealing more subtle effects that are nevertheless very behaviorally relevant. Modern mechanistic approaches have informed us greatly as to how to potentially ameliorate the induced deficits in brain formation and function, but conclude that better delineation of sensitive periods, dose-response relationships, and long-term longitudinal studies assessing future risk of offspring to exhibit learning disabilities, mental health disorders, and limited neural adaptations are crucial to limit the societal impact of these exposures.

Research focused on children and youth

We reviewed 22 articles on children and youth published in 2011 in the American Journal of Occupational Therapy and organized the articles by level of research and research type according to a framework adapted from the International Classification of Functioning, Disability and Health (ICF; World Health Organization, 2007). The largest percentage of articles described intervention effectiveness studies classified as Level III or IV. The bulk focused on the Body Function/Body Structure construct of the ICF, but as a whole the studies addressed all the constructs except Biomedical Molecular/Cellular. Rigor remains a concern, although laudable efforts have been made to increase strength of the evidence. Longitudinal, efficacy, and qualitative studies, as well as studies examining adolescents and the transition to adulthood, were absent from articles in this review and are important areas for future investigation. Several studies explicitly addressed intervention fidelity, an imperative in evidence-based research needed to move the profession toward the Centennial Vision.