At Risk in the Womb

Children who suffer the most from environmental exposures are those yet unborn because they are the least capable of fending themselves from toxic exposures. As compared to the maternal dose of exposure, the developing baby is exposed to greater amounts of environmental chemicals per pound of body weight. Early exposure to neurotoxins like lead and mercury may result in lifelong developmental effects, permanently altering a child’s intelligence and/or their development.

  • Pregnant women and women of child-bearing age are particularly at risk of lead poisoning because lead ingested can cross the placenta and affect the unborn child. The developing baby in the womb when exposed to lead is at higher risk of being born prematurely and having low-weight at birth. The mother is at higher risk of a complicated pregnancy due to lead induced hypertension. The most devastating of these effects is the increased risk of spontaneous abortion.

  • The U.S. Centers for Disease Control and Prevention recently found that 8 percent of women (1 in 12) of childbearing age had mercury in their blood exceeding levels deemed safe by the EPA. More recent analyses conducted by the U.S. Environmental Protection Agency (EPA) show that mercury levels in a fetus’ umbilical cord blood are 70 percent higher than those in the mother’s blood, nearly doubling the estimate of newborn children at risk for health problems because of unsafe mercury levels from 320,000 to 630,000. These revised estimates indicate that more than 1 in 6 children born in the U.S. could be at risk for developmental disorders because of mercury exposure in the mother’s womb.

  • Mercury accumulates in the environment and builds up in the tissue of fish and other species, including humans that eat them. Mercury affects the nervous system and is especially dangerous for pregnant women and children. The U.S. Food and Drug Administration recommends that pregnant and breastfeeding women limit their intake of large fish due to higher levels of mercury contamination. For more details on the FDA advisory for women who might become pregnant, women who are pregnant, nursing mothers and young children, click on

  • High-level prenatal exposure to mercury has been clearly associated with the development of mental retardation and cerebral palsy in infant. Lower level exposure may cause more subtle neurodevelopment deficits. Examples of problems that may arise are poor attention span and delayed language development; impaired memory and vision; problems processing information; and impaired fine motor coordination.

  • Exposure to air pollution during pregnancy, particularly during the first trimester, can affect a child’s growth (resulting in low birth weight and intrauterine growth retardation—being born at or below 10th percentile for age in weeks); can shorten the gestation period leading to preterm births; and can cause congenital birth defects such as heart problems. It can also result in the loss of life. Sudden Infant Death Syndrome (SIDS), the unexplained death of an infant while sleeping, and still births are widely recognized to be associated with outdoor air pollutant exposure in utero.

  • Polychlorinated biphenyls (PCBs) are mixtures of synthetic organic chemicals with the same basic chemical structure and similar physical properties ranging from oily liquids to waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications. More than 1.5 billion pounds of PCBs were manufactured in the United States prior to cessation of production in 1977. However, once released PCBs remain widespread in the environment for many years, and humans are exposed in multiple ways. Infants born to PCB poisoned mothers have shown numerous symptoms, including congenital birth defects, darkening of the skin and liver disease.

  • Babies exposed to high levels of PCBs during pregnancy may also have low birth weight, decreased intelligence, irritated eyes, behavioral problems, developmental delay and slowed growth.

  • Lower level exposure to PCBs in the prenatal period has been shown to have an effect on school performance, including decreased intelligence, memory and attention span.