Determining reliability of triclosan measures in pregnant women
March 13, 2014
Rounding up a large number of research subjects to come to the lab to give a urine specimen can be a daunting task. Asking them to come back repeatedly to give more specimens over several weeks usually results in some of the subjects not showing up or perhaps dropping out of the study altogether. Each request for a repeat visit holds the risk of reducing the subject pool. Every subject who drops out before the study has been completed represents lost time and money for the researchers.
An international group of researchers that included Stephanie M. Engel, PhD, associate professor of epidemiology at UNC’s Gillings School of Global Public Health, reported welcome news about the reliability of using only one specimen. The 13 researchers, divided fairly evenly between Norway and the U.S., where they came from Rochester, N.Y., Atlanta and Chapel Hill, N.C., tested pregnant women in Norway for the presence of Triclosan (TCS) in their urine throughout their pregnancy. They concluded that if a woman tested positive for TCS at one point in her pregnancy, likely all of her subsequent tests would be positive, too.
The results of their study were published online Jan. 29 in the Journal of Exposure Science and Environmental Epidemiology.
TCS is synthetic antibacterial chemical found in a number of personal care products, such as antibacterial soap, cosmetics and toothpaste. Exposure to TCS has been linked to a number of health concerns, including increased resistance to antibiotics, increased allergic reactions in children and interference with hormones, such as those that regulate the thyroid.
Many researchers would like to learn more about the effects of TCS, particularly in pregnant women, but have been hesitant to rely on the results of one positive test to extrapolate that the woman had been exposed to TCS throughout her pregnancy.
After testing 45 pregnant women at gestational weeks 17, 23 and 29, Engel and her colleagues determined that the results of one urine test would reliably reflect the results of the other two. TCS does not accumulate in the body and has a urinary half-life of about 21 hours. Women tend to use the same brands of personal care products over an extended period of time. Thus, despite TCS’s short half-life in urine, researchers could have confidence that the presence of TCS at one point in the pregnancy likely would indicate that TCS would be found in subsequent tests. With that reliability, researchers could say with confidence that one positive specimen would be sufficient to assume exposure to TCS during the pregnancy.