Mary Chris Jaklevic
December 23, 2021
Pregnant women exposed to higher levels of endocrine-disrupting plasticizers experienced steep increases in blood pressure late in pregnancy and elevated BP up to 6 years postpartum, researchers have found.
Urine samples from 892 pregnant women contained traces of nine phthalates, a ubiquitous class of synthetic chemicals used in food production and packaging, as well as cosmetics and other goods. Of 15 phthalate metabolites measured, all were detected in at least 86% of samples and a majority were in at least 99%, according to the investigators, who reported their findings December 22 in Environmental Health Perspectives.
In what the researchers said was the first examination of phthalate exposure and long-term postpartum blood pressure, statistical models showed higher combined levels of the compounds "were associated with higher gestational blood pressure during mid-to-late pregnancy through 72 months postpartum," they write.
The differences were small, about a 2.4 mm Hg increase in postpartum systolic and diastolic blood pressure between the highest and lowest exposure quintiles. Still, the authors write, "exposure to phthalates at earlier life stages may have lifelong consequences on the blood pressure trajectory, potentially elevating the risk for chronic illnesses later in life, such as hypertension."
The women were recruited in Mexico City from late 2007 to 2011 as part of the PROGRESS study. Their mean age was 27.7 years and mean BMI was 26.9 kg/m2. Seventy-four percent (661) had low socioeconomic status.
Although the study does not prove that phthalates increase blood pressure, it bolsters advice for pregnant women to reduce exposure, according to the researchers. Phthalates have been labeled a neuro-developmental risk by Project TENDR, a collaboration of scientists and public health advocates that draws attention to environmental threats to child development.
Study co-author Joseph M. Braun, RN, MSPH, PhD, associate professor of epidemiology and director of the Center for Children's Environmental Health at Brown University School of Public Health, Providence, Rhode Island, said pregnant women should be counseled to take measures such as varying their diet and using a vacuum cleaner with a high-efficiency particulate air filter — but individuals can only do so much. "We need to have sensible regulations in place to protect people from these chemicals," Braun told Medscape Medical News.
One challenge is the dynamic mix of compounds. Researchers found four of these had strong effects: Di(2-ethylhexyl) phthalate (DEHP), mono-2-ethyl-5-carboxypentyl terephthalate (MECPTP), monobenzyl phthalate (MBzP), and dibutyl phthalate (DBP).
"Of great public health concern," they write, is MECPTP, which is growing in use as a replacement for DEHP, which has been banned from certain products.
The study could not account for diet and personal care product use, two major sources of phthalate exposure. Consumption of fast foods and packaged foods may confound results because both are associated with sedentary lifestyles and high sodium diets linked to hypertension, said Nathaniel DeNicola, MD, MSHP, environmental health expert for the American College of Obstetricians and Gynecologists, which advises clinicians to counsel patients about prenatal exposure to toxins.
Yet DeNicola, of Johns Hopkins Medicine, Baltimore, Maryland, who was not involved in the study, said the findings underscore that "phthalates are probably more present and ubiquitous than we realize, and decreasing them, especially during pregnancy, is an important public health goal."
Funding for the study came from the National Institutes of Health. The authors and DeNicola have disclosed no relevant financial relationships. Braun reported having served as an expert witness for plaintiffs in litigation related to perfluoroalkyl and polyfluoroalkyl substances–contaminated drinking water but did not receive direct compensation.