Could diet be fueling pregnancy hypertension? Saliva holds the clues

During pregnancy, the body becomes particularly vulnerable to chemical exposures that can affect both the mother and the developing fetus. These exposures—often from everyday sources like processed foods, packaging materials, and personal care products—introduce xenobiotic metabolites (XMs) into the body.

While blood tests are the standard method to monitor such exposures, they are invasive and poorly suited for frequent sampling. Saliva, on the other hand, offers a painless, accessible, and data-rich alternative.

Despite its promise, saliva remains underused in exposome studies, particularly in pregnant populations. Due to these limitations, there is a growing need to harness saliva as a window into environmental chemical exposures and their biological effects during this critical life stage.

In a study published in the International Journal of Oral Science, scientists from Singapore, the U.S., and Australia reported a novel approach to exposome research by profiling saliva from 80 pregnant women.

Using advanced mass spectrometry, they mapped more than 700 metabolites and identified over 18,000 significant associations between environmental xenobiotics and metabolic pathways.

The researchers then focused on a subset of food-related chemicals and their surprising connection to elevated stress hormones and preeclampsia risk, offering new insight into how everyday exposures may be silently shaping pregnancy outcomes.

The team conducted untargeted metabolomic profiling of saliva samples collected from pregnant women between 24 and 34 weeks of gestation. They identified 582 endogenous metabolomes and 125 xenobiotic chemicals, many of which were linked to diet, food additives, or packaging materials.

Using network clustering and pathway enrichment, they uncovered a striking cluster centered on tyrosine metabolism—specifically, elevated catecholamines like dopamine, norepinephrine, and epinephrine.

Further regression analysis revealed that exposure to certain chemicals, including toluene, styrene, quinoline, and coumarin—commonly found in food packaging or flavorings—was significantly associated with higher levels of these stress hormones.

The researchers then validated these findings in a smaller group, showing that women with preeclampsia had notably higher levels of these xenobiotic chemicals compared to healthy controls. These compounds are known to inhibit monoamine oxidase (MAO), an enzyme that helps regulate neurotransmitter breakdown.

Disruption of MAO activity can lead to hormone imbalances that increase the risk of hypertensive disorders during pregnancy. The use of saliva enabled the researchers to noninvasively capture these complex biochemical interactions, offering an accessible lens into how the modern chemical landscape may influence maternal health.

"Saliva provides a unique molecular snapshot of the body's interaction with its environment," said Dr. Preethi Balan, the study's lead author.

"Our findings suggest that common chemicals in food packaging and additives—often considered harmless—can significantly impact maternal hormone regulation.

"This underscores the need for more accessible, real-time tools to monitor environmental exposures, especially in vulnerable groups like pregnant women. Saliva sampling offers a scalable and noninvasive way forward in exposome research and public health surveillance."

This research opens the door to using saliva as a front-line tool in maternal health monitoring. Unlike blood tests, saliva sampling is noninvasive, low-cost, and easy to repeat—making it ideal for tracking exposure over time.

With more widespread adoption, it could serve as an early-warning system for pregnancy complications like preeclampsia, empowering health care providers to intervene earlier. The findings also raise important questions for regulators and the food industry, as several of the implicated chemicals are preventable exposures.

Future studies involving larger, more diverse populations are needed to confirm these links and establish guidelines for reducing harmful exposures during pregnancy—ultimately safeguarding the health of mothers and babies.