Parfums, Shampoos, and Soaps: Everyday Products Can Affect Babies' Brains

Phthalates are chemicals found in many everyday products, such as plastics, cosmetics, and cleaning products. Although they are common, they can affect our hormones and cause health problems, especially during pregnancy. Studies show that exposure to these substances can alter a baby's development while still in the womb, affecting the brain and behavior in the first months of life.

Phthalates are chemicals created in the early 20th century and are present in a wide variety of everyday products, such as vinyl flooring, plastics, soaps, shampoos, cosmetics, oils, and perfumes.

They are used to make plastics more flexible and durable, and to help maintain the shine, aroma, or color of various items. Because they are found in so many objects and materials, human exposure to phthalates is constant and practically inevitable.

People come into contact with phthalates mainly through food and beverages that have been packaged in materials containing these compounds, or through the use of personal products that contain them. We can also inhale them by breathing dust that carries contaminated particles.

Once inside the body, phthalates are rapidly processed and eliminated through urine, which allows recent exposure to be measured by analyzing the metabolites present in the urine. In the United States, virtually the entire population has some detectable level of phthalates in their bodies.

Exposure to phthalates is not the same for everyone. Women tend to have higher levels than men, possibly because they use more hygiene and beauty products. In addition, studies show that black women have even higher levels than white women, which may be linked to social inequalities and environmental racism, including the specific marketing of products aimed at Afro hair, which contain higher concentrations of these substances.

These substances are of concern to scientists because they are classified as endocrine disruptors. This means that they can interfere with the functioning of the body’s hormones, even when present in small amounts.

Since hormones control a number of fundamental processes, from growth to mood, any changes can have profound effects on health. Studies have linked exposure to phthalates to a number of health problems, particularly impacts on reproduction and child development. One of the greatest risks is related to pregnancy.

Phthalates can cross the placenta and reach the developing fetus, potentially affecting the baby’s brain and behavior. Research has shown, for example, that mothers with higher levels of these substances during pregnancy gave birth to babies with lower scores on neurological tests shortly after birth.

Other studies have found links between prenatal exposure to phthalates and reduced mental and motor skills in the first few months of life. Despite this evidence, few studies have investigated how phthalates affect mothers’ metabolism during pregnancy, that is, how these substances alter the chemical processes that occur within the body.

One study analyzed mothers’ blood and placentas at the end of pregnancy and found changes in substances linked to energy and cellular function, suggesting that phthalates may disrupt these essential pathways, especially in the placenta, which is vital for the baby’s development.

More recently, researchers have begun to explore how phthalates directly affect the metabolism of newborns. In a study of pregnant black women and their babies, scientists sought to understand whether phthalate levels measured in the mothers’ urine during pregnancy were linked to changes in the babies’ metabolic profile and, consequently, to their behavior and mental health.

To do this, they analyzed blood samples from the newborns collected shortly after birth and compared them with the results of behavioral tests performed in the first weeks of life.

The results showed that exposure to phthalates was associated with important changes in metabolic pathways related to amino acids such as tryptophan and tyrosine, which play an essential role in the production of brain substances such as serotonin and dopamine, neurotransmitters linked to mood, attention and behavior.

These metabolic changes may be the first signs of how phthalates affect the developing brain.

This type of study is essential to understanding the biological mechanisms behind the effects of phthalates and could help identify biomarkers, that is, chemical signals in the body that indicate that something is wrong in development. This would allow for earlier intervention, offering better care to mothers and babies at risk, especially in more exposed and vulnerable communities.

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Impact of prenatal phthalate exposure on newborn metabolome and infant neurodevelopment

Susan S. Hoffman, Ziyin Tang, Anne Dunlop, Patricia A. Brennan, Thompson Huynh, Stephanie M. Eick, Dana B. Barr, Blake Rushing, Susan L. McRitchie, Susan Sumner, Kaitlin R. Taibl, Youran Tan, Parinya Panuwet, Grace E. Lee, Jasmin Eatman, Elizabeth J. Corwin, P. Barry Ryan, Dean P. Jones and Donghai Liang

Nature Communications. 16, Article number: 2539 (2025) 

DOI: 10.1038/s41467-025-57273-z

Abstract

We evaluated associations among exposure to prenatal phthalate metabolites, perturbations of the newborn metabolome, and infant neurobehavioral functioning in mother-newborn pairs enrolled in the Atlanta African American Maternal-Child Cohort during 2016–2018. We quantified eight phthalate metabolites in prenatal urine samples collected between 8- and 14-weeks’ (visit 1; n = 216) and 24- and 30-weeks’ gestation (visit 2; n = 145) and metabolite features in newborn dried-blood spot samples collected at delivery. Associations between phthalate metabolite concentrations and metabolic feature intensities at both visits were examined using adjusted generalized linear models (MWAS). Then, an exploratory meet-in-the-middle (MITM) analysis was conducted in a subset with NICU Neonatal Neurobehavioral Scale (NNNS) scores (visit 1 n = 81; visit 2 n = 71). In both the MWAS and MITM, many of the confirmed metabolites are involved in tyrosine and tryptophan metabolism, including tryptophan, tyrosine, thyroxine, and serine. This analysis elucidates how prenatal phthalate exposure disrupts the newborn metabolome and infant neurobehavioral outcomes.