Preterm birth risk increases for pregnant women exposed to phthalates
The odds of preterm delivery appear to increase for pregnant women exposed to phthalates, chemicals people are exposed to through contaminated food and water and in a variety of products including lotions, perfumes and deodorants, according to a study published by JAMA Pediatrics, a JAMA Network publication.
Prematurity is a leading cause of infant death and the effects of environmental exposures on preterm birth (defined as fewer than 37 weeks of gestation) are understudied. Exposure to the chemicals by women has previously been associated with disrupted thyroid hormone levels, endometriosis and breast cancer, according to the study background.
Kelly K. Ferguson, M.P.H., of the University of Michigan School of Public Health, Ann Arbor, and colleagues examined the association between phthalate exposure during pregnancy and preterm birth. The study, which was conducted at Brigham and Women’s Hospital, Boston, included 130 women with preterm birth and 352 control participants with researchers analyzing urine samples during pregnancy for levels of phthalate metabolites.
The study results indicate an association between increases in some phthalate metabolite concentrations in urine during pregnancy and higher odds of preterm birth.
“Our results indicate a significant association between exposure to phthalates during pregnancy and preterm birth, which solidifies prior laboratory and epidemiologic evidence. Furthermore, as exposure to phthalates is widespread and because the prevalence of preterm birth among women in our study cohort was similar to that in the general population, our results are generalizable to women in the United States and elsewhere. These data provide strong support for taking action in the prevention or reduction of phthalate exposure during pregnancy,” the study concludes.
(JAMA Pediatr. Published online November 18, 2013. doi:10.1001/jamapediatrics.2013.3699. )
Phthalates are plasticizer chemicals that are commonly found in products including toys, wall coverings, nail polishes and food packaging. The Food and Drug Administration states that the effect of phthalates on health remain not well-defined.
Researchers found that women who had higher phthalate metabolite levels in their urine had a higher chance of delivering a baby before full gestation, which was set at 37 weeks. Preterm birth is a leading cause of complications and infant death, the researchers noted.
“As exposure to phthalates is widespread and because the prevalence of preterm birth among women in our study cohort was similar to that in the general population, our results are generalizable to women in the United States and elsewhere,” wrote the study’s authors. “These data provide strong support for taking action in the prevention or reduction of phthalate exposure during pregnancy.”
Editor’s Note: Funding for this study was provided by the National Institute of Environmental Health Sciences, National Institutes of Health. Please see the articles for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Editorial: Environmental Phthalate Exposure and the Odds of Preterm Birth
In a related editorial, Shanna H. Swan, Ph.D., of the Icahn School of Medicine at Mount Sinai, New York, writes: “Further support for a causal relationship between prenatal phthalate exposure and spontaneous preterm delivery would come from a study that obtained biomarkers, not only of phthalate exposure, but also uterine inflammation, and showed these to be related in cases of spontaneous preterm delivery but not among those delivered preterm for a variety of medical indications. Ferguson et al have elegantly presented the rationale for such a study.
“Moreover, they have contributed the first robust study suggesting that phthalates, pervasive in the environment of prenatal women, may be important contributors to the unknown and other causes of preterm delivery,” Swan concludes.
In an accompanying editorial, Dr. Shanna H. Swan, a professor of preventive medicine and obstetrics, gynecology and reproductive science at the Icahn School of Medicine at Mount Sinai in New York, wrote that the authors “have contributed the first robust study suggesting that phthalates, pervasive in the environment of prenatal women, may be important contributors to the unknown and other causes of preterm delivery.”
Dr. Stephen E. Welty, the chief of the neonatology service at Texas Children’s Hospital in Houston, told CBSNews.com that he considered the association between preterm birth and phthalate exposure to be strong.
He admitted it would be impossible to avoid phthalates completely, but said there are some things people can do to reduce their exposure. He suggested not eating or storing food in plastic containers, because phthalates are known to leech into food items. Welty also said to be careful to use cosmetics that have even low levels of phthalates.
“I think there will come a day where we will be more aggressive about warning people about their exposures,” he said. “There may come a time where we limit our exposure to plasticizers or try and find a new one.”
(JAMA Pediatr. Published online November 18, 2013. doi:10.1001/jamapediatrics.2013.4215.)
Editor’s Note: Please see the articles for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
Dietary Phthalate Exposure in Pregnant Women
Background Phthalates are a family of synthetic chemicals with use in a variety of industrial and consumer products. Due to their ubiquity in the environment, exposures are widespread in the U.S. population. Animal studies have shown that phthalates exhibit anti-androgenic activity and disrupt normal male reproductive tract development during gestation. Similarly, human studies document associations between prenatal phthalate exposure and harmful health outcomes. Food is considered the largest source of the most toxic phthalates for the general population, however, few U.S. studies have investigated diet’s contribution to overall body burden, and none have assessed exposures specifically in pregnant women. Methods We used multivariate regression analysis to examine the association between reported dietary intake of various food groups (beef, seafood, poultry, oils, butter, lard, shortening, spices, soy, dairy products, restaurant food/delivery/take-out and fast foods, and drinks in cans and plastic) and first trimester urinary phthalate metabolite concentrations in a multicenter cohort of 283 pregnant women from Minnesota, New York, Washington, and California participating in The Infant Development and Environment Study (TIDES).
Laurel Thomas Gnagey
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