WEDNESDAY, Dec. 23, 2009 (HealthDay News) -- Among working women in the United States, teachers seem to have the lowest risk of having babies with birth defects, while those who work as janitors, scientists and electronic-equipment operators appear most at risk, researchers say.
The study looked at nearly 9,000 babies born with single or multiple birth defects, such as those affecting the eye, ear, gastrointestinal tract and mouth and face, among others. The study also included almost 3,400 children who had none of the 45 different types of birth defects considered.
The researchers tried to determine if a link existed between the likelihood of birth defects in the children, who were born between October 1997 and December 2003, and their mothers' jobs. More than three-quarters of the women had paid jobs during the period from one month before pregnancy through the first trimester.
Women who were cleaners or janitors, operators of electronic equipment and scientists were at "significantly" higher risk of having a child with birth defects, while teachers had the lowest risk, the study authors found.
There are some caveats, however. The researchers didn't analyze chemicals that the women may have been exposed to, nor did they consider the number of hours worked. Also, the findings only point to a connection between type of employment and birth defects; they don't prove that a woman's job directly affects birth defects.
The study was published online Dec. 22 in the journal Occupational and Environmental Medicine.
Learn more about birth defects from the Nemours Foundation.