THURSDAY, Feb. 24 (HealthDay News) -- Although polychlorinated
biphenyls (PCBs) were banned decades ago, they are still pervasive
in the United States and may contribute to failed in vitro
fertilization (IVF) attempts, a new study suggests.
In fact, PCBs may account for a 40 percent reduced chance of a
live birth after IVF, the researchers said.
"These findings may help explain why these chemicals were associated with fertility issues in other studies," said lead researcher John Meeker, an assistant professor of environmental health sciences at the University of Michigan School of Public Health.
Meeker noted that there is not much women can do to avoid PCBs,
since they are still found in seafood and dairy foods.
"Levels of PCBs have been declining gradually over the past couple of decades, but when or if these levels reach zero isn't known," he said.
The report is published in the Feb. 24 online issue of
Environmental Health Perspectives.
For the study, Meeker's team collected data on IVF attempts of
765 women. In addition, they tested blood samples for 57 different
Among these women, 286 gave birth, but 530 lost their babies,
the researchers found. Of those who lost their baby, 229 had
implantation failures and 301 had miscarriages.
Specifically, Meeker's group looked at blood levels of PCBs
called congeners 118, 138 and 153, along with total PCB
They found that women with the highest levels of PCB 153 and
total PCBs had twice the risk of implantation failure, compared
with women with the lowest levels.
Moreover, women with the highest levels of these chemicals were
40 percent less likely to give birth, they added.
Meeker's team noted that these data may not apply to couples not
using IVF, and may vary due to factors not accounted for in the
Commenting on the study, Dr. George R. Attia, director of the
division of reproductive endocrinology and infertility at the
University of Miami Miller School of Medicine, said that "I'm not
"This study did not show a cause-and-effect relationship between PCBs and these outcomes," he said. "We cannot say it doesn't, but neither can we say PCBs have a cause-and-effect relationship either."
Attia did not say women should not be concerned about PCB
exposure, but studies that look for a cause-and-effect relationship
are needed to prove the connection between these chemicals and
adverse IVF outcomes, he explained.
Although PCBs, which were compounds used in industrial
materials, were banned in the United States and other countries in
the 1970s, they still persist due to widespread use and resistance
to breakdown. Exposure to PCBs occurs mostly through foods and they
have been linked with reproductive problems, Meeker said.
For more information on the health effects of PCBs, visit the
U.S. Environmental Protection Agency.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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