About
Pregnancy
Antibacterial agent could cause pregnancy problems
University of
Florida
Thursday, November 4, 2010.
GAINESVILLE, Fla. — A chemical found in everything from
antibacterial soaps and lotions to socks and toothpaste may disrupt
an enzyme that plays an important role in pregnancy,
University of Florida
researchers say.
Thought to be harmless, triclosan gives many soaps and lotions their
antibacterial oomph and is found in hundreds of popular products. But a team of UF researchers led by Margaret O. James has discovered
that the chemical hinders an enzyme linked to the metabolism of
estrogen. The researchers’ findings are reported in the November
print issue of the journal Environment International.
In pregnancy, this enzyme, called estrogen sulfotransferase, helps
metabolize estrogen and move it through the placenta into the
developing fetus. There, the estrogen plays a crucial role in brain
development and the regulation of genes.
“We suspect that makes this substance dangerous in pregnancy if
enough of the triclosan gets through to the placenta to affect the
enzyme,” said James, a professor and chairwoman of
medicinal chemistry in the
UF College of
Pharmacy. “We know for sure it
is a very potent inhibitor. What we don’t know is the kinds of
levels you would have to be exposed to to see a negative effect.
“We know it is a problem, but we don’t know how much of a problem.
We need to move forward and do additional studies.”
In pregnancy, the placenta basically serves as a developing baby’s
in-womb survival kit. Almost everything the fetus gets from its
mother — namely food and oxygen — comes through the placenta. It
also creates important hormones, such as progesterone and estrogen.
Aside from the role it plays in the fetus, estrogen also affects how
much oxygen the baby gets from the mother, said
Charles Wood, a professor and chairman of physiology and
functional genomics
in the UF College
of Medicine and a
co-author of the study. All of the oxygen a baby gets from its
mother flows through the mother’s uterine artery. Without enough
estrogen, this artery can constrict, decreasing blood flow.
“If you don’t make enough estrogen you can, we think, starve the
baby of enough oxygen,” Wood said.
Estrogen is also involved in signaling the uterus to contract during
labor. But maintaining the right levels of the hormone during
pregnancy is a delicate balance, Wood says. Too much estrogen could
send the mother’s body into premature labor. Too little could hinder
the flow of oxygen. Both instances could affect how the baby’s brain
develops.
This is one of the reasons scientists are concerned about the
pregnancy-related effects of chemicals such as triclosan.
“Some of these (chemicals) can go and combine with estrogen
receptors and mimic estrogen or keep estrogen off its receptors or
change the metabolism of estrogen, which is what we are looking at
with triclosan,” Wood said.
In April 2010, the
Food and Drug Administration
decided to take a closer look at triclosan after several studies
found links to problems with hormone regulation and other possible
negative health effects. Other studies have shown that the chemical,
which cannot be broken down by bacteria, stays in the environment
long after it is used.
“Triclosan is a material that is present in the environment and
everyone has low levels. If you use products with triclosan,
you will likely have higher levels,” said Bruce Hammock, a professor
of entomology at the
University of California-Davis
who studies triclosan. “It has some real benefits but it is
certainly not risk-free.”
More studies are needed before researchers can conclude what effects
triclosan really has on human health, James said.
“The triclosan is incorporated into household products because it
inhibits bacterial growth,” James said. “But the bad thing is it has
this unexpected side effect of inhibiting this important enzyme in
the body. At this point we don’t know if the levels people are
exposed to are high enough to cause an adverse effect.”
To View:
University of Florida abstract
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