Surging rates of high blood pressure in pregnancy – does chemical exposure play a role?

Rates of high blood pressure during pregnancy have risen sharply, up 73% between 2016 and 2024, according to a report from the Centers for Disease and Control Prevention. 

The 2026 report, finding the rate of gestational hypertension jumped from 6% in 2016 to 10.4% in 2024, draws on data from U.S. birth certificates collected during this period.

The increase during this period extends an upward trend observed in previous years – rates more than doubled between 1989 and 2016. 

True rates of gestational hypertension could be even higher: the CDC notes it may be underreported on birth certificates.

Disorders affecting many

Hypertensive disorders of pregnancy, usually referred to as HDP, affect roughly 10% to 15% of pregnancies in the U.S.  

HDP is an umbrella term covering several related but distinct conditions, each with their own health risks. The CDC report focuses on one of these disorders – gestational hypertension – but any of them can pose major threats to the health of the mothers giving birth and the developing fetus:

• Chronic hypertension. High blood pressure present before pregnancy or diagnosed before 20 weeks of gestation.
• Gestational hypertension. High blood pressure that develops after 20 weeks of pregnancy, without signs of organ damage or protein in the urine.
• Preeclampsia or eclampsia. High blood pressure after 20 weeks of gestation, with the presence of protein in the urine or signs of other organ dysfunction, such as liver or kidney issues. Preeclampsia becomes eclampsia with the onset of seizures.
• Superimposed preeclampsia. New or worsening symptoms or organ dysfunction in a person with chronic hypertension diagnosed before the pregnancy. 

Long-term harms

These common pregnancy disorders are among the leading causes of illness and mortality among pregnant people in the U.S. 

Adverse health outcomes of any of these disorders have been linked to placental abruption, organ damage or failure, maternal mortality, and cardiovascular disease later in life. They can also contribute to poor birth outcomes, such as stillbirth, neonatal mortality, restricted fetal growth, preterm birth and low birthweight. 

Some of these birth outcomes, like preterm birth, are known to be associated with worse health outcomes, such as developing chronic respiratory or renal problems, later in life. 

Known HDP risk factors

A person is more likely to develop HDP if they have any of the following: 

• Pre-existing health conditions, like chronic high blood pressure, diabetes, kidney disease
• An autoimmune disease such as lupus
• Certain characteristics and types of pregnancy, such as a pregnancy of multiples, a first pregnancy, conception through IVF, or a previous history of HDP. 

Demographic factors, including being 35 or older, having obesity, income status, and race and ethnicity, have also been associated with increased risk. 

The CDC report showed that the increased rates spanned all racial and ethnic groups, though not equally. Black and Native American women had the highest overall rates, up to 12.3% for Black women and 13.2% for Native American women. 

Although the overall rate among Asian pregnant people is lower than the average, they also have experienced the steepest percentage increase, with rates more than doubling from 3.5% to 7.1% during the study period. 

Consistent with prior research, the CDC report found gestational hypertension rates were higher among people with known risks, such as obesity and pregnancy at an age over 40. 

Rates also rose across all age groups and in every body mass index category, not just among those already considered high risk. 

This finding suggests existing risk factors alone do not account for the increase, though the exact degree to which any single factor contributes to this trend remains unclear.

Could environmental chemical exposure increase the risk?

While the CDC report cites other studies on HDP risk factors, those references do not examine environmental exposures. But regular exposure to harmful chemicals in personal care products, food and water, and household items could be contributing to this rise in HDP.

Pregnancy is a period of heightened biological sensitivity to environmental chemicals. Exposure to a specific chemical can affect a pregnant person differently than it would affect someone who is not pregnant, partly because of rapid physiological changes in the body and the developing placenta.  

For instance, endocrine-disrupting chemicals, or EDCs, such as phthalates, lead and cadmium, and the “forever chemicals” known as PFAS, can interfere with hormone signaling and have been linked to worse maternal cardiometabolic health, including HDP. Research suggests that this link holds independent of established risk factors like obesity and age. 

Harmful chemical exposure may also increase risk of other conditions associated with HDP. This is because chemicals affect the same hormones and body systems. For example, EDC exposure has been linked to insulin resistance and Type 2 diabetes and metabolic disorders like obesity. 

EDC exposure may not just be a unique risk associated with HDP, but may also be a reason why certain risk factors, like obesity and diabetes, develop in the first place. 

Reducing chemical exposure may offer a way to also reduce risk of some of these established factors before they fully develop, along with managing HDP risk after these risks are already present.

Evidence of an HDP-environmental chemical exposure connection

A growing number of scientific studies show evidence of the connection between HDP and exposure to specific environmental chemicals. The chemicals are widely used in consumer products, detected in drinking water and used in industrial applications.

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PFAS

PFAS are per- and polyfluoroalkyl substances widely used in personal care products, food packaging, children’s toys and household cleaners. They are known as “forever chemicals” because they can persist in the body and do not break down in the environment.

Studies have linked exposure to some PFAS and increased risk of HDP. A 2026 study of women in Puerto Rico found a mixture of six PFAS was associated with more than double the odds of developing gestational hypertension.

Similar associations between eight PFAS and gestational hypertension were also observed in a 2022 study of pregnant people in the Boston metro area. This is consistent with an older study, where researchers used data from the C8 health studies, a large court-mandated public health investigation of the forever chemical PFOA. They reported links between PFOA exposure and several health outcomes.

The Environmental influences on Child Health Outcomes, or ECHO, cohort reported in a 2026 study that PFAS levels in the body were linked to higher odds of preeclampsia. ECHO is a National Institutes of Health-supported research program designed to enhance the health of children by combining data across multiple U.S. geographical sites. 

They also reported a suggestive association between PFOA and gestational hypertension risk, but the findings were not consistent among all study sites.

Phthalates

Based on EWG data, the average adult uses 12 personal care products a day. These products can expose people to hundreds of chemicals, including some, like phthalates, associated with health harms.

Phthalates are used to soften plastic or stabilize scents and are found in consumer products, including in personal care products, such as nail polish. Studies report associations between phthalates and HDP, but findings differ based on when during pregnancy exposure is measured and by the specific phthalate.

In a longitudinal cohort collecting data of women in Boston between 2016 and 2020, mixtures of phthalate concentrations detected in urine samples were associated with increased blood pressure during pregnancy.

A 2026 nested case-control study in China noted similar findings: Increased levels of phthalate mixtures in urine were associated with 1.49 times the odds of having had gestational hypertension.

A 2025 study of 291 pregnant people in Texas and Virginia found a replacement phthalate, diisononyl phthalate, was linked to higher odds of HDP – but only when exposure was measured during early pregnancy, not later.

Replacement phthalates are chemicals that became more popular in use after others were phased out due to concerns about their toxicity.

In a 2024 ECHO study of 3,430 pregnant participants across eight U.S. cohorts, researchers found that two-fold higher levels of certain phthalates in urine were associated with higher odds of preeclampsia/eclampsia and other hypertensive disorders of pregnancy. Exposure to a mixture of individual phthalates was also linked to higher odds of preeclampsia/eclampsia.

Flame retardants

Flame retardants are chemicals added to electronics, furniture and building materials to slow down or stop fires. These chemicals leach off into household air and dust over time, because they are not chemically bound to the products they are added to.

Only a few studies have examined whether there is a relationship between exposure to flame retardants and HDP.

A 2023 review identified just two studies that examined the link between polybrominated flame retardants, or PBDEs, and hypertensive disorders during pregnancy. The first, a case-control study in the U.S., reported increased odds of gestational hypertension for two PBDEs, BDE-66 and BDE-47. The other, a case-control study based in Iran, reported higher levels of all PBDEs were associated with 2.19 times the odds of having preeclampsia.

PBDEs were phased out of furniture, mattresses and baby products in the mid-2000s due to concerns about their toxicity. Now companies mostly use organophosphate ester flame retardants, or OPEs, as replacements. OPEs also help make plastic more flexible and are used in vinyl flooring, children’s toys and in personal care products, like nail polish.

Evidence of an association between OPEs and HDP is mixed. A small 2021 prospective cohort study of 346 pregnant women in Cincinnati found modest associations between some OPE flame retardants in urine and higher diastolic blood pressure later in pregnancy.

A more recent 2025 study of 900 pregnant women in Boston found no link to preeclampsia, though it did find some increases in continuous blood pressure measurements.

Given how few studies exist and how inconsistent their findings are, this evidence should be considered preliminary.

Bisphenols

Bisphenol A, or BPA, has been phased out of many consumer products. But it remains in epoxy resins used to line water pipes and metal food cans, and in printed thermal receipt paper. Evidence linking BPA exposure to HDP is limited to a few studies and overall is inconclusive.

A 2016 study of 481 pregnant women living in the Boston metro area found that urinary concentrations of BPA and several phthalate metabolites were associated with increased risk of preeclampsia. But this association was not observed at all doctor visits during the study period and differed by child sex.

A 2017 nested case-control study of 173 pregnancies in China found a similar link. BPA, measured in urine samples, was associated with risk of preeclampsia.

When the European Food Safety Authority reviewed this evidence in 2023, it concluded the link between BPA and preeclampsia was “as likely as not,” meaning the evidence was not strong enough to confirm a link but also not weak enough to rule one out.

Heavy metals

People can be exposed to heavy metals like lead, cadmium and mercury through drinking contaminated water, ingestion of certain foods, particularly fish, polluted air and contaminated personal care products. Several heavy metals, including lead and cadmium, are recognized endocrine disruptors.

A 2022 review noted that heavy metals like cadmium and lead have been linked to HDP. Globally, evidence linked cadmium exposure to preeclampsia, the review found. One well-known source of cadmium is cigarette smoke.

A 2026 review linked lead exposure to gestational hypertension, and a 2018 meta-analysis identified lead exposure as a significant risk factor for preeclampsia.

It’s worth noting that heavy metal levels are present at very low levels in most everyday consumer products, and U.S. regulations set limits for lead, cadmium and other heavy metals in a range of products.

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The problem of ‘regrettable substitutions’

Biomonitoring data show that levels of several once-common chemicals, like brominated flame retardants, BPA, some PFAS, and certain phthalates, have declined in the U.S. population since bans and phase-outs began, in the mid-2000s and 2010s. 

But that decline was offset by rising exposure to newer replacement chemicals with similar chemical structures, and in some cases, similar health effects. This pattern is called a “regrettable substitution.”

For example, U.S. biomonitoring data showed median BPA levels fell 15% nationwide from 2013 to 2016, but levels of its replacement bisphenol S rose 20% over the same period. 

European biomonitoring data documents the same pattern – as BPA levels fell, its replacements bisphenol S and bisphenol F rose. 

The phthalate substitute diisononyl cyclohexane-1,2-dicarboxylat showed a similar rising trend. And OPE flame retardants, which largely replaced PBDEs, are now detected in urine samples from over 95% of the U.S. population. 

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Not every chemical class follows this substitution pattern. Blood lead levels have fallen substantially since leaded gasoline and paint were phased out, without a comparable replacement taking its place. 

Concentrations of the forever chemicals PFOA and PFOS have also declined continuously since regulatory restrictions began in the early 2000s. 

Whether a chemical has been substituted or has truly declined, research continues to link even lower exposure levels to hypertensive disorders of pregnancy. 

This may point to the absence of a clearly safe exposure threshold for these endocrine-disrupting chemicals. 

Or it may reflect the fact that people are rarely exposed to one chemical at a time, and the combined effect of many low-level chemical exposures may matter more than any single compound.

Research designed to study these combined, real-world mixtures, rather than one chemical at a time, is still developing and is an important direction for future work.

How to reduce exposure to concerning chemicals

Collectively, these studies suggest that exposure to environmental chemicals during pregnancy may be one contributor to the risk of developing hypertensive disorders.  

People who want to reduce their exposure don’t have to try replacing all their belongings at once. Small changes, such as swapping out one product for a safer alternative or filtering your water, can help reduce exposure to harmful chemicals.

Here are some tips:

• Find safer personal care products free from chemicals of concern by searching EWG’s Skin Deep® database or using EWG’s Healthy Living™ app. 
• Avoid products whose labels do not disclose their fragrance. Phthalates used in personal care products might not always show up on the label if they are part of a fragrance blend. The umbrella term “fragrance” or “parfum” can contain up to 100 ingredients, some of which may be chemicals associated with health harms. 
• Consult EWG’s Tap Water Database to find which contaminants are detected in drinking water around the country. EWG’s water filter guide can help consumers match a filter to the specific contaminants in a particular location’s water and individual budget. Not every filter removes every harmful chemical.
• Choose glass, porcelain or stainless steel containers, particularly for hot food or liquids, and avoid reheating foods in plastic.
• If avoiding flame retardants in mattresses is a priority, consumers should look for a mattress or crib mattress made by a company that’s transparent about how it meets fire-safety requirements and what materials it uses in products. Or look for EWG Verified® mattresses for the highest level of confidence.