Researchers Identify 45 Everyday Chemicals in Pregnant Women - Some May Affect the Child's Development

One of the most comprehensive studies to date on chemical exposure during pregnancy has found that pregnant women are regularly exposed to dozens of chemicals found in everyday life. According to the researchers, many of these substances may influence how early a baby is born and how much it weighs at birth—both factors that can affect health well beyond infancy. The study, led by researchers at the UNC Gillings School of Global Public Health, Stanford University School of Medicine, and the Woods Institute for the Environment, was published in JAMA Network Open.

Phthalates and Substitute Chemicals Remain Widespread

The researchers found that participants were exposed to an average of 45 different chemicals. These included phthalates, alternative plasticizers, polycyclic aromatic hydrocarbons (PAHs), and halogenated phenols. Such chemicals are found in food, drinking water, air pollution, personal care products, fragrances, and a wide variety of household items. “These chemicals are difficult to avoid because they are present in a wide variety of products we use every day. It is often hard to tell whether products contain these substances, and even when we know they do, we have limited options for controlling exposure,” said lead author Jessie Buckley, PhD, professor of epidemiology at the Gillings School. “While there are some practical steps people can take, reducing harmful chemicals at the source is the most effective way to protect children and families.”

Phthalates and alternative plasticizers were among the chemicals identified in the study. These substances are commonly used in products for babies and children, including toys, diaper creams, shampoos, and other consumer goods. In 2017, the U.S. Consumer Product Safety Commission permanently banned eight commonly used phthalates in children’s toys and products or significantly restricted their use, as exposure to these chemicals can have harmful health effects. However, these restrictions did not apply to many other products that may be used during pregnancy. The new study detected several phthalates in the participants’ samples, including some that had been introduced as substitutes for previously restricted chemicals. The researchers also found a number of plasticizer compounds in the urine samples collected as part of the study.

More Than 5,000 Mother-Child Pairs Studied

The analysis included data from more than 5,000 mothers and their children born between 2000 and 2021. The researchers determined the concentration of chemicals in the mothers’ urine samples and compared these results with gestational age and birth weight.

The team examined 113 chemicals commonly found in households, as well as in the air, food, and water. On average, each sample contained 45 chemicals, with the highest number detected in a single sample being 64. The researchers then assessed the extent to which these exposures were associated with differences in gestational age and birth weight. Several phthalates and alternative plasticizers were consistently associated with shorter pregnancies. Phthalates, alternative plasticizers, and PAHs were also linked to lower birth weight. In addition, some chemicals identified in the study that had previously been less studied—including halogenated phenols—showed associations with lower birth weight.

The researchers also identified newer plasticizers that had been introduced as alternatives to chemicals—such as phthalates—that are widely recognized as toxic. However, the study found that these substitute chemicals appeared to have similar health effects to the substances they were intended to replace.

Researchers Call for Stricter Chemical Safety Guidelines

“Our study underscores the need for stricter guidelines to protect people from toxic chemicals,” said lead researcher Dr. Tracey Woodruff, a professor of epidemiology and public health at Stanford University. “For example, we found that several newer chemicals used as substitutes for toxic substances are also harmful. This underscores why new and substitute chemicals must be properly evaluated before they are introduced to the market. Furthermore, government agencies assessing health risks from toxic chemicals such as phthalates should take our findings into account to reduce exposure and ensure healthier pregnancies.”

Buckley explained that the findings add to a growing body of evidence highlighting the importance of limiting chemical exposure during pregnancy. “Our study, along with other similar findings, underscores how important it is to reduce chemical exposure that affects pregnancy, as even small changes in birth weight or gestational age can have significant impacts on children’s health,” said Buckley. Woodruff pointed out that many sources of exposure are difficult for individuals to control on their own. “Pregnant women are at risk of chemical exposure from various sources, many of which are beyond their control,” said Woodruff. “Governments and companies must do more to reduce harmful chemicals in everyday products and ensure that new chemicals are safe—this will lead to healthier children and families.” The research findings presented in this publication were supported by the “Environmental influences on Child Health Outcomes” (ECHO) program of the Office of the Director of the National Institutes of Health.

What is the Situation in Europe?

In Europe, too, pregnant women are exposed to a wide variety of chemicals in their daily lives, including plasticizers, bisphenols, and other endocrine-disrupting substances. However, the situation is not entirely comparable to that in the U.S., as the European Union has introduced stricter regulations and restrictions for many problematic chemicals. Nevertheless, European biomonitoring studies show that certain industrial chemicals are still detectable in the human body. Exposure to such substances is being critically examined, particularly during pregnancy, as the development of the unborn child can be especially sensitive to endocrine-disrupting chemicals. Research is ongoing to determine whether—and to what extent—these exposures actually affect the duration of pregnancy, birth weight, or the long-term health of children.

What Can Pregnant Women Do to Reduce their Exposure to Chemicals in Everyday Life?

It is virtually impossible to completely avoid environmental chemicals in daily life, as many substances are widespread and come from various sources. However, a few simple measures can help reduce personal exposure:

• Buy food as fresh and unpackaged as possible: Fruit, vegetables, and other foods should not be stored in plastic packaging for extended periods whenever possible. Washing fruits and vegetables can also reduce residues of pesticides and dirt.
• Avoid contact between plastic and hot food: Food should not be heated in plastic containers whenever possible. Glass, stainless steel, or ceramic containers can be alternatives for storage and reheating.
• Avoid unnecessary fragrances: Scented cosmetics, air fresheners, and strongly scented cleaning products may contain various chemical ingredients. Fragrance-free products are often a good choice, especially during pregnancy.
• Choose cosmetics carefully: Using fewer products and avoiding unnecessary skincare items can reduce the number of potential contact substances. If you’re unsure, certified natural cosmetics or products with transparent ingredient lists can serve as a guide.
• Ventilate regularly and reduce dust: Many chemicals from furniture, electronics, textiles, or household products can bind to dust. Regular ventilation and damp mopping can lower indoor exposure levels.
• Be cautious when renovating: Paints, varnishes, adhesives, and new furniture can temporarily release increased amounts of certain chemicals into the indoor air. Renovation work should be done before pregnancy, if possible, or with adequate ventilation.

These measures can reduce personal exposure to certain chemicals but are no substitute for political and societal measures to limit problematic substances. Pregnant women should not put pressure on themselves to achieve a completely “chemical-free” environment—that is not realistic in everyday life. What is crucial, rather, is to reduce avoidable exposure while maintaining a balanced diet, staying active, and receiving good medical care during pregnancy.