Should Pregnant Women Be Concerned About BPA?
BY STEVE HENTGES | NOVEMBER 28TH 2016 06:32 AM

A recent study from French government researchers reported new results on theexposure of pregnant women to more than 100 substances that might be a concern
for the health of a developing fetus. The study examined exposure to various
metals (e.g., lead, mercury, arsenic) and many common organic compounds that
we might encounter in our daily lives.
Included in the study was bisphenol A (BPA), which is used primarily as a building
block to make polycarbonate plastic and epoxy resins. Although those names may
be unfamiliar to you, the materials are not; both are used in countless productsthat we use every day.
Polycarbonate is a clear, durable and lightweight plastic that is used in a diverse
range of products from bicycle helmets to eyeglass lenses. Epoxy resins are toughand chemically resistant materials that excel in applications that require a
protective coating (e.g., anti-rust primer on automobile bodies) or a material that isboth high strength and lightweight (e.g., wind energy turbine blades).
The French researchers reported that the majority of women in their study wereexposed to BPA and provided quantitative data on the levels of exposure. Missing
from the paper was any context to help us understand whether we should be
alarmed or comforted by their findings. In other words, are the exposure levels
safe or not?
Coincidentally, a group of Greek scientists recently published their assessment ofBPA in the peer-reviewed scientific literature and concluded that “exposure to BPA
does not pose any significant threat according to most realistic exposure
scenarios.” The conclusion is well supported by a set of complementary analyses
that specifically included pregnant women. The conclusion of the Greek scientists
is also consistent with and further supports the science-based conclusions ofgovernment bodies worldwide on the safety of BPA.

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New French Study on BPA Exposure to Pregnant Women
An increasingly accepted way to measure human exposure to chemicals is throughbiomonitoring studies, which measure the level of a chemical in biological samples
such as urine or blood. For BPA, analysis of urine is most appropriate since BPA is
rapidly eliminated from the body in urine within hours of exposure. By measuring
what comes out of the body, urine biomonitoring measures exposure to BPA fromall sources over the last day or so. When applied to a representative group ofpeople, urine biomonitoring provides a reasonable estimate of average exposure toBPA across a population.
The new study was conducted by a team of researchers from Santé publiqueFrance, which is the French national public health agency and is responsible for theFrench Human Biomonitoring Program. In this study, BPA was measured in theurine of more than 1,700 pregnant women who gave birth in France in 2011. Dueto the study design, the results provide an estimate of exposure that isrepresentative of the population of French pregnant women in that year. The
results are important since pregnant women might generally be considered one of
the most vulnerable subpopulations for exposure to chemicals.
Not surprisingly, considering how widely it is used, BPA was quantified at low levelsin the urine of almost 74% of pregnant women, indicating that exposure to BPA iscommon. The median BPA level (0.75 micrograms/liter) is comparable to theresults of a large-scale study of pregnant women in Canada from a similar time
period. The BPA levels measured in the French study are also comparable to theresults of biomonitoring studies from the same time period that are representativeof the U.S. population.
Comparison of the BPA levels with the levels of metals and other organic chemicals
measured in the French study reveals that the BPA levels are relatively
low. However, the French researchers did not include information in their paper tohelp us understand whether the levels are safe.

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How Can We Evaluate Safety?
With thousands of studies published in the scientific literature, BPA is almost
certainly one of the best tested substances in commerce. Many studies, including
the new French biomonitoring study, report that people are exposed to BPA at lowlevels, but exposure studies alone can’t tell us whether the levels are safe. Afterall, we’re exposed to many chemicals that occur naturally in our diet, but we don’t
conclude that our diet is unsafe just because we can (and do) measure exposure to
those chemicals.
An even larger number of studies, typically conducted on laboratory animals,
report various health effects that might be caused by exposure to BPA, but thesestudies alone also can’t tell us whether BPA is safe. Health effects have also been
identified for the chemicals that occur naturally in our diet, even for vitamins andother essential nutrients, but that doesn’t make them unsafe.
We can evaluate safety by combining information on exposure and health effects ina scientific process known as a safety or risk assessment. Health effect information
tells us what effects can be caused by exposure to a chemical and, most critically,at what exposure level the health effects might occur. Exposure information thentells us whether actual exposures are above or below the critical level.

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What Do the New BPA Exposure Results Mean?
Just before the new biomonitoring study was published, a group of researchers in
Greece published their assessment of BPA. Jumping to the bottom line, they
concluded that “exposure to BPA does not pose any significant threat according tomost realistic exposure scenarios.” Since their analysis explicitly included pregnant
women, their conclusion is particularly applicable to the exposure levels measured
in pregnant women in France.
What the Greek scientists did was focus on the exposure side of the safetyassessment equation with four complementary analyses. Of particular relevancefor the French biomonitoring data is that they calculated a “biomonitoringequivalent” (BE) based on the conservative safe intake level for BPA recently
established by the European Food Safety Authority. The BE level represents theestimated concentration of BPA in urine corresponding to intake of BPA at the safe
intake level.
The median BPA level measured in the French study is more than 400 times below
the BE level. This indicates that not only are the actual French exposure levels
safe, but they’re safe with a wide margin of safety. It’s not even close.
The other three analyses from the Greek scientists gave consistent results andprovide further support for the safety of the French exposure levels. The Greek
scientists also stated that “there is no reason for concern based on either individual
or aggregate scenarios of BPA exposure.” That conclusion is consistent with theviews of government bodies worldwide that have recently evaluated the safety ofBPA, for example the U.S. Food and Drug Administrationand the European Food
Safety Authority.
What Else Does the French Study Tell Us?
Careful inspection of the data table in the French study reveals another very
important piece of information. Although we may frequently say that urine
biomonitoring measures the level of BPA in urine, as is stated above in this article,
that’s not exactly what is measured.

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The data table indicates that urine was monitored for both “unconjugated” and“total” BPA. Unconjugated BPA, which is simply BPA itself, was found but could only
be quantified at very low levels in about 10% of the urine samples.
Total BPA consists almost entirely of a metabolized form of BPA. From many otherstudies on laboratory animals and, most importantly people, we know that BPA isefficiently converted in the body to a biologically inactive metabolite, which is thenrapidly eliminated in urine. It is this metabolized form of BPA that was found in
approximately 74% of the urine samples.
The urine biomonitoring data from the French study confirms that this important
metabolic process occurred in the French pregnant women. As a result, since themetabolite is biologically inactive and rapidly eliminated from the body, BPA is not
likely to cause health effects at the low exposure levels measured in the study.

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