Alcohol and cigarette smoking have a powerfully adverse effect on a fetus’s development and are frequently underestimated as a cause of cerebral palsy.  Questionnaires and reports to insurance companies often do not indicate if the mother smoked or abused alcohol.

Fetal alcohol syndrome debilitates a number of systems and can cause cerebral palsy.  It has been estimated that eight percent of children suffering from fetal alcohol syndrome later contract cerebral palsy.  This percentage may be higher in developing nations where the abuse of alcohol may go unnoted.

Cigarette smoking lowers birth weight.  Low birth weight and premature birth are primary risk factors for cerebral palsy.  This variable is another one that may not be revealing itself in real numbers.

Cocaine and crack use by the mother during pregnancy can result in a number of serious problems for the fetus, including central nervous system damage, autism, brain damage, organ impairment, blood vessel complications, low birth weight, and premature birth.  Frequently, by the time the cerebral palsy is diagnosed, the link to the mother's actions during pregnancy is lost.

Environmental agents can contribute to causation, some occurring outside the awareness of the mother or even the culture.  These variables are particularly difficult to isolate because they can work in association with other factors.  One of the first documented cases of environmental agents negatively influencing the growth of the fetus occurred in Japan.  In Minamata Bay, between 1953 and 1971, there was an epidemic of cerebral palsy because pregnant women were consuming fish contaminated with methyl mercury from a chemical plant.

Sources
Bachrach, Steven J., and Miller, Freeman.  Cerebral Palsy: A Complete Guide for Caregiving.  Baltimore: The Johns Hopkins University Press, 1995.

Hart, Hilary M., ed.  Clinics in Developmental Medicine.  London:  Mac Keith Press.   Alberman, Eva; Blair, Eve; and Stanley, Fiona.  Cerebral Palsies: Epidemiology and Causal Pathways.  London:  Cambridge University Press, 2000.  (The book is part of a series of hardcover monographs published by Mac Keith Press.  Four new ones are published each year.  The distributor is Cambridge University Press.)

Stanton, Marion.  The Cerebral Palsy Handbook:  A Practical Guide for Parents and Carers.  London:  Vermillion, 2002.