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Jonah’s mother was a heroin addict. Shortly after birth, it was obvious Jonah was in withdrawal. His jittery movements and crying persisted for the next 2 days and there was little anyone could do to console him. He scratched his face trying to get his hands to his mouth. His knees and elbows were rubbed raw from his agitated movements, and the muscles in his tiny legs were so stiff that it was difficult to straighten his legs to diaper him.
Source: www.cmiproject.net
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The full extent of the effects of prenatal drug exposure on a child is not known, however studies show that various drugs of abuse may result in premature birth, miscarriage, low birth weight, and a variety of behavioral and cognitive problems.
| Drugs that may have adverse prenatal effects: |
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| Selected Research Findings on the Prenatal Effects of Drug Abuse |
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Prenatal Marijuana Exposure and Academic Achievement at Age 10 Years
University of Pittsburgh researchers have reported their latest findings from a longitudinal cohort study of children exposed to marijuana in utero. In this study, women were interviewed about their substance use at the end of each trimester of pregnancy, and at multiple times during the child's development. The children were assessed on physical, emotional, and cognitive development at 8 and 18 months, and at 3, 6, 10, 14, and 16 years postpartum. This report provides findings on academic achievement at age 10 (606 children were assessed), using the Wide Range Achievement Test-Revised (WRAT-R), the reading comprehension subtext of the Peabody Individual Achievement Test-Revise (PIAT-R), and teacher reports of child performance in school. As a group, the women were of lower socioeconomic status, high-school-educated, light-to-moderate users of marijuana and alcohol, and equally distributed in terms of race/ethnicity (Caucasian and African-American). Exposure to one or more marijuana joints per day during the first trimester predicted deficits in WRAT-R reading and spelling scores, and a lower rating on the teachers' evaluations of the children's performance. These associations existed when home environment, race/ethnicity, socioeconomic status, and other prenatal substance exposure were controlled. However, these associations were mediated by effects of first-trimester marijuana exposure on the children's symptoms of depression and anxiety. Second-trimester marijuana use was associated with reading comprehension and underachievement. Exposure to alcohol during the first and second trimesters predicted poorer teacher ratings of overall school performance, whereas second-trimester binge drinking predicted lower reading scores. There was no interaction between prenatal marijuana and alcohol exposure. Each was an independent predictor of aspects of academic performance. The investigators compared their findings to those of the other cohort study of prenatal marijuana exposure reported in the literature, and they discussed possible reasons for differences in findings on school performance between the two studies. The investigators also discuss the limitations of the analyses and of the generalizability of the findings. Goldschmidt, L., Richardson, G.A., Cornelius, M.D., and Day, N.L. Prenatal Marijuana and Alcohol Exposure and Academic Achievement at Age 10. Neurotoxicology and Teratology, 26, pp. 521-532, 2004.
Cognitive Outcomes of Preschool Children with Prenatal Cocaine Exposure
Researchers at Case Western Reserve University report that 4-year-old children who were exposed to cocaine in utero scored significantly lower on some specific measures of intelligence than did children who were not exposed to the drug in utero. The two groups did not differ on overall, verbal, and performance IQ scores, although exposed children were less likely to have above-average overall IQ. The study results also suggest that mentally stimulating home environments may positively affect brain development and lessen prenatal effects of cocaine. At 4 years of age, 190 cocaine-exposed and 186 nonexposed children were assessed using the Wechsler Preschool and Primary Scales of Intelligence-Revised. This test revealed that exposed children had lower scores than nonexposed children in the specific areas of information, arithmetic, and object assembly (reflecting visual-spatial skills). In arithmetic skills, cocaine-exposed boys had lower scores than girls and nonexposed boys. The researchers also compared two groups within the cocaine-exposed children, i.e., 148 cocaine-exposed children living with their biological mothers or other relatives, and 42 cocaine-exposed children living in adoptive or foster care. They found that 25 percent of cocaine-exposed children living with their mothers or relatives had overall IQ scores lower than 70, compared with only 10 percent of cocaine-exposed children in adoptive or foster care. The researchers report that caregivers in the adoptive and foster homes were better educated, and had better vocabulary and intelligence test scores than the caregivers who were family members. Additional findings indicated that adoptive or foster care was associated with a lower rate of mental retardation in the cocaine-exposed children, despite the fact that these children had been exposed to twice as much cocaine while in utero, and that the cocaine-exposed children in the more stimulating environments had IQ scores that were similar to those of nonexposed children. The findings of this study are consistent with and expand on other preschool cocaine-exposure studies that show specific (but not global) IQ deficits. The results also emphasize how important it is to examine childrearing environments when assessing developmental progress of drug-exposed children, and they also provide optimism that interventions may be effective for children who are affected by prenatal cocaine exposure. Singer, L.T., Minnes, S., Short, E., et al. Cognitive Outcomes of Preschool Children with Prenatal Cocaine Exposure. JAMA, 291(20), pp. 2248-2456, 2004.
Maternal Substance Use Patterns During Pregnancy and Infant Growth Parameters at Birth
Maternal cocaine use during pregnancy has been associated with decreased growth parameters in multiple previous studies. Women who use cocaine often use other substances as well (e.g., alcohol and tobacco, both of which have been shown to have effects on birth weight). A recent publication from the Maternal Lifestyle Study (MLS) reported on how patterns of cocaine, alcohol, tobacco, and marijuana use during pregnancy were related to infant birth weight, length, and head circumference in a sample of 651 mothers and their infants. Because cocaine use has been associated with preterm delivery, only term pregnancies were evaluated for this report. The MLS is a multisite longitudinal study of in utero drug exposure that is jointly funded by NICHD and NIDA. It is the largest study of its type. Histories of substance use were obtained for the 3-month period before pregnancy and the three trimesters of pregnancy. Patterns of use were categorized for each substance as consistently high, moderate, or low/none, and increasing or decreasing. The effects on growth parameters were analyzed in multivariate linear regression analyses, with adjustment for clinical site, maternal age, prepregnancy weight, multidrug use, and socioeconomic status. Detailed results of use patterns and growth parameters are reported in the publication. Overall, with adjustments made for confounders, including multi-drug use, patterns of tobacco use during pregnancy were associated with deficits in birth weight, length, and head circumference, whereas cocaine use was linked to deficits in birth weight and head size. In addition, birth weight, length, and head circumference were significantly greater among infants born to women who used no drugs compared to women with any cocaine, opiate, alcohol, tobacco, or marijuana use during pregnancy. The investigators emphasize that a clinical implication of the study is the importance of curtailing use during pregnancy of illicit drugs as well as alcohol and tobacco. Shankaran, S., Das, A., Bauer, C.R., et al. Association between Patterns of Maternal Substance Use and Infant Birth Weight, Length, and Head Circumference. Pediatrics, 114(2), pp. e226-e234, 2004.
| Relevant NIDA Meetings |
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On March 23-24, 2004, a meeting entitled Long-Term Follow-Up of Prenatal Drug Exposure: Advances, Challenges, and Opportunities was held in Bethesda, MD. The meeting was co-sponsored by NIDA, NICHD, and ORWH, NIH. Twenty-three longitudinal cohort studies were represented, and a total of more than 100 individuals attended the meeting. In addition to reports on progress and directions for all ongoing studies, there were sessions on neuroimaging in the cohort studies, genetic analyses, and relevant toxicological procedures. Group discussions addressed issues of measurement (e.g., risk and resiliency factors, substance abuse vulnerability), methodological considerations in longitudinal data analyses, and biological and social/environmental mechanisms underlying associations between prenatal exposure and developmental outcomes. The meeting was organized and co-chaired by Drs. Vincent Smeriglio (NIDA), Rosemary Higgins (NICHD), and Loretta Finnegan (ORWH). Other NIDA members involved in the meeting were Drs. Marilyn Huestis and Joni Rutter, both of whom made presentations, and Drs. Jonathan Pollock, Laurence Stanford, and Cora Lee Wetherington, each of whom chaired sessions.
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