Newborns whose mothers drank alcohol heavily during pregnancy had damage to the nerves in the arms and legs, according to a study by researchers at the National Institute of Child Health and Human Development, one of the National Institutes of Health. The study was conducted in collaboration with researchers at the University of Chile.
The nerve damage was still present when the children were reexamined at one year of age.
The study is the first to examine whether exposure to alcohol before birth affects the developing peripheral nervous system-the nerves in the arms and legs, rather than in the brain or spinal cord. The study appears in the March issue of the Journal of Pediatrics.
"Infants born to mothers who drink heavily during pregnancy are known to be at risk for mental retardation and birth defects, said Duane Alexander, M.D., director of the NICHD. "This is the first study to show that these infants may suffer peripheral nerve damage as well."
Adults who drink excessive amounts of alcohol can experience peripheral neuropathy, a condition that occurs when nerves involved in communication between the central nervous system (the brain and spinal cord) and the rest of the body are damaged. This can lead to tingling sensations, numbness, pain or weakness.
The NICHD-University of Chile Alcohol and Pregnancy Study compared 17 full-term, newborn infants whose mothers drank heavily during pregnancy to 13 newborns not exposed to alcohol in the womb. "Heavy drinking" is defined as having four standard drinks per day (one standard drink is equivalent to one can of beer, one glass of wine or one mixed drink). All women identified as heavy drinkers were advised that their drinking habits were potentially dangerous to their fetus and were offered help from an alcohol counseling clinic to stop drinking alcohol or to cut down on their drinking.
All of the children underwent a complete neurological exam followed by testing of the nerves in their upper and lower limbs. The researchers stimulated the nerves using a machine that passed a very mild electric current through the skin and then recorded the electrical activity of the nerves to determine if they were normal or damaged. (The procedure uses a current mild enough not to cause pain.) The nerve studies were performed when the children were about one month old and again when they were 12 to 14 months old.
The children exposed to alcohol before they were born experienced significant problems in conducting a message through the nerves--both at one month and one year of age. The alcohol-exposed children did not experience any catch-up or improvement in nerve function by the time they reached their first birthday.
"The finding that the nerve damage persisted when the children were a year old suggests that alcohol may cause permanent damage to developing nerves," said James L. Mills, MD, MS, director of the study and chief of the Pediatric Epidemiology Section in the Division of Epidemiology, Statistics and Prevention Research at the NICHD. "Because the children were evaluated before they could talk, they were unable to tell us if they had symptoms such as pain or numbness. We are continuing to follow these children to determine what effect this nerve damage will have on normal nerve function and whether it will lead to weakness or problems with touch sensation or fine motor skills later in life."
The National Institute on Alcohol Abuse and Alcoholism recommends that pregnant women not consume any alcohol. Information on the hazards of alcohol use during pregnancy is available at http://pubs.niaaa.nih.gov/publications/DrinkingPregnancy_HTML/pregnancy.htm.
The NICHD is part of the National Institutes of Health (NIH), the biomedical research arm of the federal government. NIH is an agency of the U.S. Department of Health and Human Services. The NICHD sponsors research on development, before and after birth; maternal, child, and family health; reproductive biology and population issues; and medical rehabilitation. NICHD publications, as well as information about the Institute, are available from the NICHD Web site, http://www.nichd.nih.gov, or from the NICHD Information Resource Center, 1-800-370-2943; e-mail NICHDInformationResourceCenter@mail.nih.gov.