Jennifer A. Willford

Prenatal alcohol and marijuana exposure: effects on neuropsychological outcomes at 10 years.

This report from a longitudinal study of the effects of prenatal alcohol and marijuana exposure investigates whether these drugs affect neuropsychological development at 10 years of age. Women were recruited from a medical assistance prenatal clinic and interviewed about their substance use at the end of each trimester of pregnancy, at 8 and 18 months, and at 3, 6, 10, 14, and 16 years. Half of the women were African American, and half were Caucasian. The women were generally from lower socioeconomic status families and had obtained high school degrees. At the 10-year follow-up, 593 children completed a neuropsychological battery, which focused on problem solving, learning and memory, mental flexibility, psychomotor speed, attention, and impulsivity. Prenatal alcohol use was found to have a significant negative impact on learning and memory skills, as measured by the WRAML. Prenatal marijuana exposure also had an effect on learning and memory, as well as on impulsivity, as measured by a continuous performance task. The effects of prenatal alcohol and marijuana exposure persisted when other predictors of learning and memory were controlled. We continue to follow these offspring into the adolescent years when further neuropsychological deficits may become evident.

Verbal and visuospatial learning and memory function in children with moderate prenatal alcohol exposure.

BACKGROUND This study investigated the effects of moderate prenatal alcohol exposure on learning and memory in 14-year-old adolescents. The Childrens Memory Scale was used to assess learning and memory function in the verbal/auditory and visual/spatial domains. In addition, both short- and long-term memory function were assessed. METHODS Data were collected as part of the Maternal Health Practices and Child Development Project, a longitudinal study including 580 children and their mothers. Women were assessed during each trimester of pregnancy and with their children from birth to 16 years of age. At age 14, memory function was evaluated using the Childrens Memory Scale, an assessment tool that measures learning and immediate and delayed memory function in the verbal and visual-spatial domains. RESULTS Prenatal alcohol exposure during the first trimester predicted deficits in learning, short-term memory, and long-term memory, specifically in the verbal domain. Deficits in performance were specific to learning and memory of word-pairs. In addition, deficits in memory were mediated by learning performance. CONCLUSIONS Results demonstrated that prenatal alcohol exposure lead to deficits in encoding processes as indicated by deficits in verbal learning. Initial deficits in acquisition were responsible for deficits in immediate and delayed recall of verbal information in children who were exposed to alcohol during pregnancy but did not have fetal alcohol syndrome.

Prenatal tobacco effects on neuropsychological outcomes among preadolescents

This study evaluated the relationships between maternal smoking during pregnancy and 10-year-old childrens performance on measures of learning, memory, and problem-solving. In this prospective cohort study, mothers were recruited from an urban prenatal clinic in 1982 and 1983 and observed from their fourth prenatal month until the time of the study. At the 10-year visit, 593 children and mothers were evaluated. The prevalence of tobacco use was high in this cohort: 54.3%, 53.3%, and 60% of the women smoked in the first trimester, third trimester, and 10-year assessment, respectively. After controlling statistically for other prenatal substance use, current tobacco, other substance use variables, and multiple sociodemographic covariates, prenatal tobacco exposure was significantly associated with deficits in learning and memory. Specifically, prenatal tobacco exposure was associated with deficits in verbal learning and design memory, as well as slowed responding on a test of eye-hand coordination. In addition, these children demonstrated a reduced ability for flexible problem solving and more impulsivity, as indicated by an increase in perseverative responses on a card-sorting test. Prenatally exposed children did not show attention deficits or increased activity on a continuous performance test.

Prenatal Marijuana Exposure and Intelligence Test Performance at Age 6

OBJECTIVE This is a prospective study of the effects of prenatal marijuana exposure on the intelligence test performance of 648 children at a 6-year follow-up. METHOD Women were interviewed about the amount and frequency of their marijuana use at 4 and 7 months of pregnancy and at delivery. Participants were light to moderate users of marijuana and represented a lower income population. Children were assessed with the Stanford-Binet Intelligence Scale by examiners blind to exposure status. Multiple regression was applied to examine the effects of prenatal marijuana exposure on childrens intelligence after partialing out the effects of other significant predictors. RESULTS There was a significant nonlinear relationship between marijuana exposure and child intelligence. Heavy marijuana use (one or more cigarettes per day) during the first trimester was associated with lower verbal reasoning scores on the Stanford-Binet Intelligence Scale. Heavy use during the second trimester predicted deficits in the composite, short-term memory, and quantitative scores. Third-trimester heavy use was negatively associated with the quantitative score. Other significant predictors of intelligence included maternal IQ, home environment, and social support. CONCLUSIONS These findings indicate that prenatal marijuana exposure has a significant effect on school-age intellectual development.

Effects of prenatal cigarette smoke exposure on neurobehavioral outcomes in 10-year-old children of adolescent mothers.

In this prospective study, adolescent mothers (mean age=16; range=12-18; 70% African-American) were interviewed about their tobacco use during pregnancy. When their children were ten, mothers reported on their childs behavior and the children completed a neuropsychological battery. We examined the association between prenatal cigarette smoke exposure (PCSE) and offspring neurobehavioral outcomes on data from the 10-year phase (n=330). Multivariate regression analyses were conducted to test if PCSE predicted neurobehavioral outcomes, adjusting for demographic characteristics, maternal psychological characteristics, prenatal exposure to other substances, and exposure to environmental tobacco smoke. Independent effects of PCSE were found. Exposed offspring had more delinquent, aggressive, and externalizing behaviors (CBCL). They were more active (Routh, EAS, and SNAP) and impulsive (SNAP) and had more problems with peers (SNAP). On the Stroop test, deficits were observed on the more complex interference task that requires both selective attention and response inhibition. The significant effects of PCSE on neurobehavioral outcomes were found for exposure to as few as 10 cigarettes per day. Most effects were found from first trimester PCSE exposure. These results are consistent with results from an earlier assessment when the children were age 6, demonstrating that the effects of prenatal tobacco exposure can be identified early and are consistent through middle childhood.

The Effects of Prenatal Cocaine Use on Infant Development

This study examined the effect of prenatal cocaine use on infant physical, cognitive, and motor development, and temperamental characteristics, controlling for other factors that affect infant development. Women were, on average, 26.8 years old, had 12 years of education, and 46% were African American. During the first trimester, 18% were frequent users of cocaine (> or =1 line/day). The infants were, on average, 14.6 months old at this follow-up phase. Women who used cocaine during pregnancy rated their infants as more fussy/difficult and unadaptable than did women who did not use cocaine. Cocaine use in the second trimester was associated with significantly lower motor scores on the Bayley Scales of Infant Development (BSID) [N. Bayley, Manual for the Bayley Scales of Infant Development, Psychological Corporation, New York, 1969.]. There was no effect of prenatal cocaine use on BSID mental performance or on growth. These findings are consistent with other reports in the literature and with the hypothesis that prenatal cocaine exposure affects development through changes in neurotransmitter systems.

School achievement in 14-year-old youths prenatally exposed to marijuana

The relation between prenatal marijuana exposure (PME) and school achievement was evaluated in a sample of 524 14-year-olds. Women were recruited during pregnancy and assessed, along with their offspring, at multiple phases from infancy to early adulthood. The sample represents a low-income population. Half of the adolescents are male and 55% are African American. School achievement was assessed with the Wechsler Individual Achievement Test (WIAT) Screener (Psychological Corporation, 1992). A significant negative relation was found between PME and 14-year WIAT composite and reading scores. The deficit in school achievement was mediated by the effects of PME on intelligence test performance at age 6, attention problems and depression symptoms at age 10, and early initiation of marijuana use. These findings suggest that the effects of PME on adolescent achievement are mediated by the earlier negative effects of PME on child characteristics. The negative impact of these characteristics on adolescent achievement may presage later problems in early adulthood.

Effects of prenatal tobacco, alcohol and marijuana exposure on processing speed, visual-motor coordination, and interhemispheric transfer.

Deficits in motor control are often reported in children with prenatal alcohol exposure (PAE). Less is known about the effects of prenatal tobacco exposure (PTE) and prenatal marijuana exposure (PME) on motor coordination, and previous studies have not considered whether PTE, PAE, and PME interact to affect motor control. This study investigated the effects of PTE, PAE, and PME as well as current drug use on speed of processing, visual-motor coordination, and interhemispheric transfer in 16-year-old adolescents. Data were collected as part of the Maternal Health Practices and Child Development Project. Adolescents (age 16, n=320) participating in a longitudinal study of the effects of prenatal substance exposure on developmental outcomes were evaluated in this study. The computerized Bimanual Coordination Test (BCT) was used to assess each domain of function. Other important variables, such as demographics, home environment, and psychological characteristics of the mother and adolescent were also considered in the analyses. There were significant and independent effects of PTE, PAE, and PME on processing speed and interhemispheric transfer of information. PTE and PME were associated with deficits in visual-motor coordination. There were no interactions between PAE, PTE, and PME. Current tobacco use predicted deficits in speed of processing. Current alcohol and marijuana use by the offspring were not associated with any measures of performance on the BCT.

Continued effects of prenatal cocaine use: Preschool development

The relationship between prenatal cocaine use and preschoolers physical and cognitive development and behavioral characteristics was examined, controlling for other influences on child development. On average, children were 38.5 months old, women were 29.4 years old, had 12.3 years of education, and 47% were African American. During the first trimester, 18% of the women were frequent cocaine users (> or = 1 line/day). First trimester cocaine exposure predicted decreased head circumference at 3 years and lower scores on the short-term memory subscale of the Stanford-Binet Intelligence Scale (SBIS) [74]. There was no significant relationship between prenatal cocaine use and the other SBIS scales. First trimester cocaine use also predicted more total, internalizing, and externalizing behavior problems on the Child Behavior Checklist [3] and higher scores on the fussy/difficult scale of the Infant Characteristics Questionnaire [6]. Children who were exposed to cocaine throughout pregnancy had more behavior problems and were more fussy compared to children of women who never used cocaine prenatally. A repeated measures analysis showed that children of first trimester cocaine users became more fussy over time. These detrimental effects on growth and behavior are consistent with other reports in the literature and with the hypothesis that prenatal cocaine exposure affects development through changes in neurotransmitter systems.

Prenatal cocaine exposure: Effects on mother- and teacher-rated behavior problems and growth in school-age children.

In this longitudinal study of prenatal cocaine exposure (PCE), school-age physical and cognitive development and behavioral characteristics were examined, while controlling for other factors that affect child development. At this follow-up phase, children were on average 7.2 years old, and their caregivers were 33.7 years old, had 12.5 years of education, and 48% were African American. During the first trimester, 20% of the women were frequent cocaine users (≥1 line/day). First trimester cocaine exposure predicted decreased weight and height at 7 years. There was no significant relationship between PCE and the cognitive and neuropsychological measures. Third trimester cocaine use predicted more total and externalizing behavior problems on the Child Behavior Checklist (Achenbach, 1991 [3]) and the Teacher Report Form (Achenbach, 1991 [4]), and increased activity, inattention, and impulsivity on the Routh Activity (Routh et al., 1974 [67]) and SNAP scales (Pelham and Bender, 1982 [55]). Children who were exposed to cocaine throughout pregnancy had more mother- and teacher-rated behavior problems compared to children of women who stopped using early in pregnancy or who never used cocaine prenatally. These detrimental effects of PCE on behavior are consistent with other reports in the literature and with the hypothesis that PCE affects development through changes in neurotransmitter systems. These school-age behaviors may be precursors of later adolescent behavior problems.