Researchers at Harvard have discovered that fragrance chemicals hidden in baby lotions and shampoos may contribute to dangerous blood pressure spikes during pregnancy. A new study published in the Journal of the Endocrine Society found that pregnant women with higher levels of phthalates in their bodies had measurably elevated blood pressure, particularly in the final trimester, increasing their risk for serious pregnancy complications.

What Are Phthalates and Why Are They in Baby Skincare?

Phthalates are synthetic chemicals that serve two main purposes in manufacturing: they make plastics more flexible and durable, and they act as fixatives in fragrances, helping scents bind to skin and last longer. This second function is what makes them so common in personal care products like baby lotion, shampoo, and other skincare items. The problem is that consumers cannot easily identify them on product labels.

Under a 1966 federal law called the Fair Packaging and Labeling Act, manufacturers can list "fragrance" or "parfum" as a single ingredient on cosmetic labels, even when that fragrance contains dozens or hundreds of individual chemical compounds, including multiple types of phthalates. The law treats fragrance formulas as trade secrets, so companies are not required to disclose which specific chemicals are hiding under that single word. This means parents buying baby skincare products have no way of knowing whether phthalates are present.

What Did the Harvard Study Find About Pregnancy and Blood Pressure?

Researchers from Harvard T.H. Chan School of Public Health tracked 338 pregnant women enrolled in the Environmental Reproductive and Glucose Outcomes (ERGO) Study, collecting urine samples and blood pressure readings at three points during pregnancy: at a median of 11, 19, and 26 weeks of gestation. The team measured concentrations of 18 different phthalate and replacement chemical metabolites to assess exposure levels.

The results were striking. Women with the highest levels of monoethyl phthalate (MEP), a metabolite of diethyl phthalate (DEP) commonly used in fragrances and cosmetics, had systolic blood pressure readings 4.59 millimeters of mercury higher than women with the lowest levels. Women with the highest overall personal care product phthalate concentrations showed systolic readings 5.78 millimeters of mercury higher. Diastolic blood pressure elevations of 4.51 to 4.70 millimeters of mercury were also observed in the final trimester.

Among the 338 participants in the study, 12.7 percent, or 43 individuals, developed a hypertensive disorder of pregnancy during the research period.

"Our study suggests that having higher concentrations of personal care products-associated chemicals, known as phthalates, in the body might contribute to elevated blood pressure in pregnancy," said Kimberly Parra, Ph.D., lead author of the study. "While our study does not show that phthalates cause high blood pressure during pregnancy, it suggests that reducing exposure to this class of chemicals by limiting personal care products containing these ingredients, particularly those with fragrance, may be a way to address high blood pressure in pregnancy and improve pregnancy health."

Kimberly Parra, Ph.D., Harvard T.H. Chan School of Public Health

Why Does This Matter for Maternal Health?

Hypertensive disorders of pregnancy, which include gestational hypertension, preeclampsia, eclampsia, and HELLP syndrome, are among the leading causes of maternal death in the United States. According to the American College of Obstetricians and Gynecologists, roughly 10 percent of all U.S. pregnancies are complicated by a hypertensive disorder. Preeclampsia specifically affects 2 to 8 percent of pregnancies globally and is linked to more than 50,000 maternal deaths and 500,000 fetal deaths worldwide each year.

In the United States alone, 649 women died of maternal causes in 2024, at a rate of 17.9 deaths per 100,000 live births. Hypertension-related disorders are consistently identified among the top contributors to that toll. The racial disparity in maternal mortality is stark: in 2024, the maternal mortality rate for Black women in the U.S. was 44.8 per 100,000 live births, more than three times the rate for White women at 14.2 per 100,000 live births.

Research published in Obstetrics and Gynecology found that 60 percent of preeclampsia-related maternal deaths were deemed potentially preventable, with provider responses to clinical warning signs identified as the most common failure point. The ERGO study's findings matter because they suggest an upstream prevention strategy: if personal care product exposure is a modifiable contributor to gestational blood pressure elevation, reducing that exposure during pregnancy could be one lever for improving outcomes.

How to Reduce Phthalate Exposure During Pregnancy and Early Parenthood

• Check for "fragrance-free" labels: Look for baby skincare products explicitly labeled "fragrance-free" or "unscented." These products are formulated without added fragrance chemicals and are less likely to contain hidden phthalates, though it is important to verify the full ingredient list when possible.
• Avoid products with "fragrance" or "parfum" listed: Any personal care product that lists "fragrance" or "parfum" as an ingredient may contain phthalates. This includes baby lotions, shampoos, body washes, and scented oils used on infants or during pregnancy.
• Request ingredient transparency: Contact manufacturers directly to ask whether their fragrance formulations contain phthalates. Some companies are beginning to disclose this information voluntarily, even though they are not legally required to do so under current regulations.
• Consider unscented alternatives for pregnancy: During pregnancy, switching to fragrance-free versions of essential skincare products like lotion and shampoo is a practical way to reduce exposure to this class of chemicals without sacrificing basic hygiene or skin care.

What About Current Regulations and Labeling Laws?

The Modernization of Cosmetics Regulation Act of 2022 (MoCRA) introduced meaningful improvements to the Food and Drug Administration's (FDA) cosmetics oversight authority, including adverse event reporting requirements, good manufacturing practice standards, and mandatory disclosure of fragrance allergens. However, MoCRA left the "fragrance" trade-secret framework intact. Phthalates used in fragrance formulations are still not required to be disclosed on product labels.

This regulatory gap means that even as awareness of phthalate risks grows, pregnant women and parents shopping for baby skincare products have limited tools to protect themselves through label reading alone. The study authors emphasize that reducing exposure to fragrance-containing personal care products is one of the most accessible levers pregnant women have to protect themselves, since it does not require a prescription or medical intervention.

The findings add a critical new dimension to longstanding concerns about chemical exposure during pregnancy and point toward one of the most accessible ways pregnant women can take action: the products they choose off the shelf. While the researchers note that their study should be interpreted as hypothesis-generating rather than conclusive, the biological plausibility of the findings and the stakes involved in maternal health make this an important consideration for expectant parents and healthcare providers alike.