Medical Syndromes Associated with Mental RetardationTammi Reynolds, BA & Mark Dombeck, Ph.D.Pregnancy-related problems in the mother can cause mental retardation in the developing fetus. Drug or alcohol use during pregnancy can adversely affect the baby's development, contributing to the outcome of mental retardation. For example, alcohol passes through the mother's placenta and directly affects the developing fetus. If enough alcohol is consumed, the baby's physical and mental development will be seriously and negatively altered. Smoking can also contribute to mental retardation. When a pregnant woman smokes, her fetus does not receive an adequate supply of oxygen. In addition to an inadequate oxygen supply, the fetus of a smoking woman is exposed to a number of harmful substances contained in cigarette smoke. Environmental exposure can affect a child via pre- or post-natal (before or after birth) exposure. Environmental factors that often contribute to mental retardation include toxins such as lead and mercury. Mercury can be found in polluted air and water. The single largest source of environmental mercury exposure typically occurs when pregnant women eat large quantities of ocean fish such as shark, tuna, and swordfish. When a pregnant woman eats a substantial amount of contaminated fish, the mercury contained in the fish builds up in her system. Unfortunately most of this mercury crosses the placenta, where it in turn affects the developing fetus. Another heavy metal that affects fetal development is lead. While lead can be introduced to the fetus prior to birth through the mother's food and environmental conditions, it is also present as a component of paint used in pre-1970s houses. It also may be present in soil surrounding older houses. Young children may end up poisoning themselves with lead by eating paint chips or contaminated soil. Pregnant women should take steps to severely limit their consumption of contaminated fish. They should also make sure that their home has had a 'lead abatement' treatment, during which lead paint areas are sealed with fresh paint and contaminated soils are replaced or covered with plant material to make it less likely to be consumed. | 
