Dioxin linked to breast feeding ills

ROCHESTER, N.Y., June 12 (UPI) -- Dioxin exposure during pregnancy can harm fast-changing breast tissue cells and that may cause some women to have trouble breast feeding, U.S. researchers said.

Corresponding author B. Paige Lawrence of the University of Rochester Medical Center said dioxins are generated mostly by the incineration of municipal and medical waste, especially certain plastics. Most people are exposed through diet.

Dioxins also get into the food supply when air emissions settle on farm fields and where livestock graze. Also, fish ingest dioxins and related pollutants from contaminated waters, Lawrence said.

The study, published in the journal Toxicological Sciences, showed that dioxin has a profound effect on breast tissue by causing mammary cells to stop their natural cycle of proliferation as early as six days into pregnancy and lasting through mid-pregnancy.

In tissue samples from mice, exposure to dioxin caused a 50-percent decrease in new epithelial cells. This is important, Lawrence said, because mammary glands have a high rate of cell proliferation, especially during early to mid-pregnancy when the most rapid development of the mammary gland occurs.

Researchers also found that dioxin altered the induction of milk-producing genes, which occurs around the ninth day of pregnancy, and decreased the number of ductal branches and mature lobules in the mammary tissue.