FRIDAY, Nov. 23 (HealthDay News) -- Children of women exposed to arsenic-contaminated water during pregnancy have gene expression changes that may result in cancer and other diseases later in life, a Massachusetts Institute of Technology study suggests.

The researchers, who said their work is the first documentation of widespread genetic changes caused by prenatal exposure to an environmental contaminant, analyzed umbilical cord blood from the children of 32 mothers in an area of Thailand with heavy mining-related arsenic contamination. Similar levels of arsenic are found in many other parts of the world, including the U.S. Southwest.

Children who were exposed to arsenic in the womb had about 450 genes that were either significantly more active (in most cases) or less active than the same genes in unexposed children.

Most of the gene expression changes detected in the exposed children are associated with inflammation, which can lead to increased cancer risk. It's not clear how long these gene expression changes may last, and the researchers plan to continue testing the children.

The researchers also found that a subset of 11 of these genes could be used as a highly reliable test for determining whether a child had been exposed to arsenic while in the womb.

The study was published in the Nov. 23 issue of the journal PLoS Genetics.

More information

The U.S. Agency for Toxic Substance and Disease Registry has more about arsenic.