Lead author Sarah Santiago, a Ph.D. candidate, and Kelly Huffman, an assistant professor, both at the University of California, Riverside, and undergraduate student Grace Park of the University of California, San Diego, surveyed 200 pregnant or recently pregnant women ages 18-40 -- 87 percent Hispanic -- in Downey, Calif., from December 2011 to December 2012.
Nearly all had a high school degree, and about one-fourth had a college or post-graduate degree. More than two-thirds had an annual income of $50,000 or less.
Using a food questionnaire, participants reported how often and when during their pregnancy they ingested certain foods, beverages and medications.
The study, published in Nutrition Journal, found about three-quarters ate fish, typically tuna, tilapia and salmon; three-fourths ate canned goods, 12 percent consumed tap water, 80 percent consumed caffeinated beverages and about 6 percent reported drinking alcohol sometime during their pregnancy, the study said.
Most reported taking prenatal vitamins, nearly half reported taking an over-the-counter medication -- primarily acetaminophen -- at least once and most reported taking prescription medications at least once.
"Tuna contains methylmercury, and prenatal exposure has been associated with numerous developmental deficits, while 'staggering' levels of polychlorinated biphenyls -- PCBs -- were found in farmed salmon," the study said.
"Metal food cans are lined with a plastic that contains bisphenol A, which leaches from the lining in cans into the food. In Downey, eight pollutants found in drinking water exceeded the health guidelines set by federal and state agencies."
"Prenatal medical professionals should discourage the consumption of dangerous foods, beverages and medications that women commonly report consuming during pregnancy," the researchers said.
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