Toronto, (IANS) Expectant mothers in their first trimester should avoid certain cosmetics, cleaning agents and medicines, to protect the developing fetal brain from chemicals that can trigger autism, suggest health researchers from York University in Canada.

"The products that we use on a daily basis, such as creams and cosmetics, contain chemicals that could potentially affect a developing baby during pregnancy," said one of the researchers professor Dorota Crawford.

Besides cosmetics and lotions, the list of products that expectant mothers should avoid during first trimester, according to the researchers, include - cleaning solvents, pesticides, nonsteroidal anti-inflammatory drugs such as acetylsalicylic acid, misoprostol (a drug used for inducing labour), polychlorinated bisphenyls used as industrial lubricants, polybrominated diphenyl ethers found in wood and textiles, phthalates in PVC flooring, and children's toys.

Aside from the type of chemical a pregnant woman is exposed to, the duration, the frequency and the concentration level also impact a developing brain at the prenatal stage, the researchers said.

"We recommend that women learn about health effects from exposure to chemical substances in the environment," study co-author Christine Wong noted.

According to the researchers, prenatal brain development undergoes constant changes and its normal functioning depends greatly on the presence of specific genes at any given time.

Since environmental factors influence the expression levels of these critical genes, it is important for an expectant mother to be aware and cautious of exposure to these factors.