Preterm birth is more likely with phthalate exposure

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Monday, July 11, 2022

NIH study of pregnant women confirms link to chemicals that may endanger pregnancy.

Pregnant women who were exposed to multiple phthalates during pregnancy had an increased risk of preterm birth, according to a new study from the National Institutes of Health. Phthalates are chemicals used in personal care products, such as cosmetics, as well as in solvents, detergents and food packaging.

After analyzing data from more than 6,000 pregnant women in the United States, researchers found that women with higher concentrations of certain phthalate metabolites in their urine were more likely to deliver their babies preterm, which is giving birth three or more times. many weeks before the mother’s due date.

“Having a preterm birth can be dangerous for both the baby and the mother, so it’s important to identify risk factors that can prevent it,” said Kelly Ferguson, Ph.D., an epidemiologist at the Institute National Institute of Environmental Health Sciences (NIEHS). , part of the NIH, and senior author of the study published in the journal JAMA Pediatrics.

*In this study, the largest study to date on this topic, Ferguson and her team pooled data from 16 studies conducted across the United States that included individual participant data on prenatal urinary phthalate metabolites (which represent exposure to phthalates) as well as delivery time. The researchers analyzed data from a total of 6,045 pregnant women who gave birth between 1983-2018. Nine percent, or 539, of the women in the study gave birth prematurely. Phthalate metabolites were detected in more than 96% of urine samples.

Higher concentrations of most of the phthalate metabolites examined were associated with slightly higher odds of preterm birth. Exposure to four of the 11 phthalates found in pregnant women was associated with a 14-16% greater probability of having a preterm birth. The most consistent findings were for exposure to a phthalate commonly used in personal care products such as nail polish and cosmetics.

The researchers also used statistical models to simulate interventions that reduce phthalate exposure. They found that reducing the mixture’s phthalate metabolite levels by 50% could prevent preterm births by an average of 12%. Behavioral interventions, such as trying to choose phthalate-free personal care products (if listed on the label), voluntary actions by companies to reduce phthalates in their products, or changes in standards and regulations can contribute to reducing exposure. and protection of pregnancies.

“It is difficult for people to completely eliminate exposure to these chemicals in everyday life, but our results show that even small reductions within a large population can have positive impacts on both mothers and their children,” said Barrett Welch, Ph.D. a postdoctoral fellow at NIEHS and first author on the study.

Eating fresh, home-cooked foods, avoiding processed food that comes in plastic containers or wraps, and choosing products that are unscented or labeled “phthalate-free” are examples of things people can do that can reduce their exposure. Changes in the amount and types of products containing phthalates can also reduce exposures.

Researchers are conducting additional studies to better understand the mechanisms by which exposure to phthalates may affect pregnancy and to determine whether there are effective ways for mothers to reduce their exposure.

Grants: This research was supported in part by the NIEHS Intramural Research Program.
(Z01ES103333), and extramural grants from NIEHS (P42ES017198, P30ES005022, R21ES031231, P01ES009605, R01ES021369, R01ES02438, R01ES030078, R01ES016863, P42ES017198, R01ES022934, P30ES010126, P01ES09584, R01ES013543, R01ES014393, R01ES08977, R01ES009718, ES013543, P30ES023513, R01ES031591, P42ES017198, R01ES031657, P01ES022844, R01ES017500, P30ES005022, T32ES007018, R01ES0125169-01, R21ES025551, R24ES028533, R01ES016863-04, R01ES016863-02S4, P30ES005022, P01ES011261), NCI (R21CA128382), NIDDK (R01DK076648), NICHD (R21HD058019), NIH OD (UH3OD023251 , UH3OD023365, UH3OD023342), US EPA (R82670901, R827039), and NCATS (UL1TR001881).

About the National Institute of Environmental Health Sciences (NIEHS): NIEHS supports research to understand the effects of the environment on human health and is part of the National Institutes of Health. For more information on NIEHS or environmental health topics, visit or subscribe to a news list.

About the National Institutes of Health (NIH):NIH, the national medical research agency, includes 27 institutes and centers and is a component of the US Department of Health and Human Services. The NIH is the lead federal agency that conducts and supports basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for common and rare diseases. For more information about NIH and its programs, visit

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Welch BM, Keil AP, Buckley JP, Calafat AM, Christenbury KE, Engel SM, O’Brien KM, Rosen EM, James-Todd T, Zota AR, Ferguson KK, and Phthalate Exposure and Preterm Birth Study Group. Associations between prenatal urinary biomarkers of phthalate exposure and preterm birth A pooled study of 16 US cohorts. JAMA Pediatrics; doi:10.1001/jamapediatrics.2022.2252. Published online on July 11, 2022.


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