Barbara Watkinson

Differential effects on cognitive functioning in 13- to 16-year-olds prenatally exposed to cigarettes and marihuana

Cognitive performance was examined in 145 thirteen- to sixteen-year-old adolescents for whom prenatal exposure to marihuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing, longitudinal study. The assessment battery included tests of general intelligence, achievement, memory, and aspects of executive functioning (EF). Consistent with results obtained at earlier ages, the strongest relationship between prenatal maternal cigarette smoking and cognitive variables was seen with overall intelligence and aspects of auditory functioning whereas prenatal exposure to marihuana was negatively associated with tasks that required visual memory, analysis, and integration. The interpretation of the results is discussed in terms of the differential observations related to in utero exposure to cigarettes and marihuana and the nature of the cognitive variables associated with the two drugs.

36- and 48-month neurobehavioral follow-up of children prenatally exposed to marijuana, cigarettes, and alcohol.

Aspects of neurobehavioral development were examined in 133 36-month- and 130 48-month-old children for whom prenatal exposure to marijuana, cigarettes, and alcohol had been previously ascertained and who have been assessed since birth. Parallelling earlier observations made with this sample at 12 and 24 months, prenatal exposure to cigarette smoking was significantly associated with poorer language development and lower cognitive scores at both 36 and 48 months after statistically controlling for confounding factors. Relatively low levels of maternal alcohol consumption, which had measurable effects at 24 and 36 months, no longer had significant relationships with outcome variables at 48 months of age. At 48 months, significantly lower scores in verbal and memory domains were associated with maternal marijuana use after adjusting for confounding variables. This negative relationship is the first reported association beyond the neonatal stage, and may represent a long-term effect of the drug upon complex behavior that, at a younger age, had not developed and/or could not be assessed.

12- and 24-month neurobehavioural follow-up of children prenatally exposed to marihuana, cigarettes and alcohol

The motor, mental, and language development plus the home environment was examined in 217 twelve-month and 153 twenty-four-month-old children for whom prenatal exposure to marijuana, alcohol and cigarettes was previously ascertained. With this low-risk sample multiple regression analysis was used to assess the association between outcome measures and prenatal drug exposure while adjusting for potential confounding factors. Prenatal exposure to marijuana was uniquely positively associated with a series of items evaluating the childs attitudes and interests that reflect a cognitive factor. Moderate levels of alcohol were significantly associated with lower mental scores at 24 months of age. Prenatal maternal cigarette smoking was significantly associated with lower mental scores at 12 months of age and altered responses on auditory items at 12 and 24 months. However, at 24 months, the strong relationship of postnatal environmental factors with cognitive outcomes and with prenatal maternal smoking resulted in loss of significant, unique predictive power for maternal smoking. Based on the present work and supplemented by previously reported data pertaining to maternal attitudes during pregnancy and neonatal behaviour, a transactional interpretation is presented.

A COMPARISON OF ACTIVE AND PASSIVE SMOKING DURING PREGNANCY : LONG-TERM EFFECTS

Previous research has determined that maternal smoking during pregnancy is associated with negative effects for the child at birth and throughout childhood. Much less is known about the consequences of exposure to secondary smoke during fetal development. The present study investigates and compares the long-term consequences of active and passive smoking during pregnancy. Ninety-one children between the ages of six and nine years were tested using a comprehensive neuropsychological test battery. After considering potential confounds, children of nonsmoking mothers generally were found to perform better than the two smoking groups on tests of speech and language skills, intelligence, visual/spatial abilities and on the mothers rating of behavior. The performance of children of passive smokers was found, in most areas, to be between that of the active smoking and nonsmoking groups. It was concluded that there is a continuum of long-term smoking effects and that, although active maternal smoking is associated with effects of greater breadth and magnitude than passive maternal smoking, children of passive smokers are also at risk for a pattern of negative developmental outcomes.

Reading and language in 9- to 12-year olds prenatally exposed to cigarettes and marijuana.

Facets of reading and language were examined in 131 9- to 12-year-old children for whom prenatal exposure to marijuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle class sample who are participants in an ongoing longitudinal study. Discriminant Function Analysis revealed a dose-dependent association that remained after controlling for potential confounds, between prenatal cigarette exposure and lower language and lower reading scores, particularly on auditory-related aspects of this latter measure. The findings are interpreted as consistent with earlier observations of an association between cigarette smoking during pregnancy and altered auditory functioning in the offspring. Similarities and differences between the reading observations and dyslexia are discussed. Maternal prenatal passive smoke exposure did not appear to contribute to either the language or reading outcomes at this age but postnatal secondhand smoke exposure by the child was associated with poorer language scores. Prenatal marijuana exposure was not significantly related to either the reading or language outcomes.

Neonatal Neurological Status in a Low-risk Population after Prenatal Exposure to Cigarettes, Marijuana, and Alcohol

The neurological status of 9− and 30-day-old infants, as assessed by the Prechtl neurological examination, was significantly and differentially related to prenatal exposure of cigarettes, marijuana, and alcohol. Data on approximately 250 babies, born to healthy, white, predominantly middle-class women, were analyzed using discriminant function analyses controlling for potentially confounding variables. Prenatal cigarette exposure was associated with hypertonicity and increased nervous system excitation, particularly at 30 days, prenatal marijuana exposure was associated with symptoms similar to mild narcotic withdrawal, and prenatal exposure to relatively low levels of alcohol was associated with slightly lowered nervous system arousal at 9 days of age. The results were related to behavioral observations on neonates exposed to drugs prenatally. J Dev Behav Pediatr 8:318–326, 1987. Index terms: cigarettes, marijuana, alcohol, neonatal neurological status, withdrawal.

Differential effects on facets of attention in adolescents prenatally exposed to cigarettes and marihuana

Facets of attention were examined in 152 13- to 16-year-old adolescents for whom prenatal exposure to marihuana and cigarettes had been ascertained. The subjects, participants in an ongoing longitudinal study, were from a low-risk, predominantly middle-class sample. The assessment battery included 11 variables derived from a Continuous Performance Test, the Wisconsin Card Sorting Test, the Stroop Test, a number of memory tasks and four subtests of the Wechsler Intelligence Scale for Children. A principal components analysis yielded a five-factor model that was highly concordant with a recent model of attention proposed by Mirsky. Prenatal cigarette exposure was associated with an encode/retain (working memory) component of attention and, at the younger age, with the impulsivity element. Prenatal marihuana was associated with the factor describing stability of attention over time. The differential drug findings were consistent with and extend observations noted when this sample was assessed at earlier ages.

Central auditory processing in school-age children prenatally exposed to cigarette smoke

One hundred and ten, 6- to 11-year-old children from a low-risk, predominantly middle class sample who are participants in an ongoing longitudinal drug study were assessed using a central auditory processing task (SCAN) that made perceptual rather than linguistic demands. Maternal smoking during pregnancy was linearly associated with poorer performance on the overall SCAN and, particularly, the Competing Words subtest which may be an indication of the childs auditory maturation. The significant associations remained after adjusting for other drug use, demographic variables, and passive smoke exposure both during pregnancy and postnatally. The childs recent second-hand smoke exposure was evaluated by a parental questionnaire and by urine cotinine assay. Neither prenatal nor postnatal passive smoke exposure was statistically significantly associated with the SCAN results. However, among the children of nonsmokers, passive smoke exposure resulted in average scores similar to those of the prenatal light smoking group. The findings are discussed in relation to earlier observations that have reported an association between smoking during pregnancy and altered auditory functioning in the offspring.

Growth from birth to early adolescence in offspring prenatally exposed to cigarettes and marijuana.

Weight, height, and head circumference were examined in children from birth to early adolescence for whom prenatal exposure to marijuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing longitudinal study. The negative association between growth measures at birth and prenatal cigarette exposure was overcome, sooner in males than females, within the first few years, and by the age of six, the children of heavy smokers were heavier than control subjects. Pre and postnatal environmental tobacco smoke did not have a negative effect upon the growth parameters; however, the choice of bottle-feeding or shorter duration of breast-feeding by women who smoked during pregnancy appeared to play an important positive role in the catch-up observed among the infants of smokers. Prenatal exposure to marijuana was not significantly related to any growth measures at birth, although a smaller head circumference observed at all ages reached statistical significance among the early adolescents born to the heavy marijuana users.

Growth and pubertal milestones during adolescence in offspring prenatally exposed to cigarettes and marihuana.

Weight, height, head circumference, and pubertal milestones were examined in one hundred fifty-two 13- to 16-year-old adolescents for whom prenatal exposure to marihuana and cigarettes had been ascertained. The subjects were from a low-risk, predominantly middle-class sample participating in an ongoing, longitudinal study and whose growth has been monitored since birth. The weight of the 13- to 16-year-old children of heavy cigarette smokers, after statistical adjustment, did not differ from control subjects but they had a significantly higher Ponderal Index (PI). These observations continued those noted when these subjects were 9 to 12 years of age. Among the male offspring of cigarette smokers, pubertal milestones occurred at an earlier age than among male adolescents born to nonsmokers. Active smoking by the offspring did not moderate these findings. Maternal marihuana use was not associated with any growth measurement or the timing of pubertal milestones.