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Does Maternal Smoking Affect Infant Language?
By Claire D. Coles, Ph.D.
Although most women who abuse alcohol and other
drugs also smoke cigarettes, the effect of prenatal exposure to
tobacco is not well explored. The negative effects of smoking
on birth weight were known and women in the 1960's were warned
not to smoke when pregnant to avoid having a low birth weight
baby. However, we were also told that the baby's weight would
quickly "catch up" following birth and that there were
no other negative consequences. Over time, some other problems
were identified particularly in children who lived with smokers
and were exposed to what is called ETS (environmental tobacco
smoke).
These problems including increased respiratory infections
and asthma and a higher risk for sudden infant death syndrome
(SIDS). Children who were exposed to this "secondary smoke"
also seemed to have more ear infections (called "otitis media").
Little attention was paid to cognitive or behavior effects until
a Canadian-based study (Fried, et al. 1997) published information
suggesting that middle class children exposed prenatally to tobacco
had more problems with language and reading than did similar children
whose mothers did not smoke.
Following up on Fried's work, the Maternal Substance
Abuse and Child Development Project in Georgia, found that 6-month
olds who were exposed to nicotine had more problems than other
children in processing sounds (Kable, 1995). When these children
were 4 ½ years old, they showed problems with "auditory
processing" of words that they heard. That is, they were
not able to make fine discriminations between different syllables
like "bat" and "pat" and would sometimes confuse
words that sounded the same. This problem is of particular concern
because children with reading disabilities show the same difficulties.
To investigate this problem in greater depth, the
Emory Language Development Study was funded by the National Institute
on Child Health and Human Development (NICHD). At the present
time, mothers who deliver at Northside and Crawford Long Hospitals
in Atlanta are eligible to participate in the study and their
infants are followed at the Emory MSACD laboratory until they
are 24 months old. During three follow-up visits, data are collected
on the baby's ability to discriminate sounds (for instance, "ba"
and "da") as well as on language development. Speech
and language will be analyzed by scientists at Emory and at Georgia
State University. When the study is completed, we will better
understand how exposure to nicotine during pregnancy and in the
home affect this important part of children's development. Having
this information will help health care professionals advise mothers
about smoking in pregnancy and will let women make a more informed
choice about continuing to smoke.
References:
Fried, P.A., Watkinson, B., & Siegel, L.S. (1997). Reading
and language in 9-to 12-year olds prenatally exposed to cigarettes
and marijuana. Neurotoxicology and Teratology, 19(3), 171-183.
Kable, J.A. (1995). Auditory vs. general information processing
deficits in infants of mothers who smoke during pregnancy. Available
from the MSACD Project.
The Maternal Substance Abuse and Child Development Project is funded in part by the Georgia Department of Human Resources Division of Public Health.

The Maternal Substance Abuse and Child Development
Study is under the direction of Claire D. Coles Ph.D., with the
Department of Psychiatry and Behavioral Science, Emory University
School of Medicine. For more information, please contact: Claire
D. Coles: ccoles@emory.edu
Karen K. Howell: khowell@emory.edu
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