ECHO Study Investigates Relationship Between Phthalate Exposure and High Blood Pressure, Related Complications During Pregnancy

Authors: John Meeker, Jordan Kuiper, et al.

Who sponsored this study?

The Environmental influences on Child Health Outcomes (ECHO) Program, Office of the Director, National Institutes of Health supported this research.

Why was this study needed?

High blood pressure during pregnancy, which can develop into the more serious conditions of preeclampsia* or eclampsia*, can pose significant health risks to pregnant women and their children. Potential environmental risk factors for ongoing high blood pressure during pregnancy and more severe pregnancy complications like preeclampsia or eclampsia have not been well-studied. Phthalates are chemicals used in various products, including plastics, personal care products, and food packaging. There is evidence, though limited, that exposure to some phthalates may be associated with preeclampsia and ongoing high blood pressure during pregnancy.

*Preeclampsia and eclampsia are pregnancy-related high blood pressure disorders. In preeclampsia, the mother’s high blood pressure reduces the blood supply to the fetus, which may get less oxygen and fewer nutrients. Eclampsia is when pregnant women with preeclampsia develop seizures or coma.

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What were the study results?

The researchers evaluated phthalate exposure by measuring urine levels of certain metabolites, which are small molecules the body makes when it breaks down foods, drugs, chemicals, or its own tissues (for example, fat or muscle tissue). This study found that higher levels of these metabolites were associated with a higher risk of developing preeclampsia, eclampsia, and/or ongoing high blood pressure during pregnancy. For example, a doubling of mono (3-carboxypropyl) phthalate (MCPP)—a metabolite linked to phthalates found in PVC-based plastics and insect repellents—was associated with 12% increased risk of developing preeclampsia or eclampsia.

For combined exposures, researchers divided participants into four groups, or quartiles, by increasing level of exposure. A quartile increase in the combined phthalate mixture was associated with a 27% increased risk of preeclampsia or eclampsia. This effect was generally larger among pregnant participants carrying female fetuses.

What was this study's impact?

The findings of this study suggest that exposure to certain phthalates found in plastics and other consumer products may be associated with pregnancy complications like gestational hypertension or preeclampsia.

Who was involved?

The study included data from 3,430 participants from eight ECHO sites across the U.S. which enrolled pregnant participants from 1999 to 2019.

What happened during the study?

The researchers measured the levels of 13 metabolites linked to phthalate exposure in urine samples collected at least once during pregnancy. They then evaluated the association between individual phthalates, as well as the combined mixture of phthalates, with the risk of developing preeclampsia, eclampsia, or ongoing high blood pressure during pregnancy.

Note: Results reported here are for a single study. Other or future studies may provide new information or different results. You should not make changes to your health without first consulting your healthcare professional.

What happens next?

Additional well-designed studies are needed to better understand the association between phthalate exposure and high blood pressure during pregnancy, the underlying biological mechanisms, and effective interventions that could reduce the risk of these kinds of pregnancy complications.

Where can I learn more?

Access the full journal article, titled “Urinary concentrations of phthalate metabolites in relation to preeclampsia and other hypertensive disorders of pregnancy in the Environmental influences on Child Health Outcomes (ECHO) program,” in Environment International.

The content is the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Published May, 2024

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