Taking steps to reducing your exposure to PCBs, (polychlorinated biphenyls) could confer added protection to your IVF cycle, increasing your chances of conceiving. A number of different studies show that the higher your exposure levels to these environmental contaminants, the greater your risk of IVF failure.
Although the production of PCBs has been banned in the US since 1977, PCBs take a long time to break down and are still recycling through the environment. Your biggest source of exposure is likely to be through your diet, the fish in your diet to be precise.
Fish are known to bioaccumulate PCBs especially wild caught bottom-feeding fish which ingest PCBs from the sludge at the bottom of lakes and rivers. This problem is magnified in wild fish from waters that already have a high PCB load such as the great lakes.
However, the real risk lies in consumption of farmed salmon. Research has shown that farmed salmon contains sixteen times more PCBs than wild salmon and contains more PCBs than other animal foods. According to the Environmental Working Group (ewg.org) "a serving of farmed salmon has up to 40 times more PCBs than other fish."
Reducing fish consumption and choosing to eat only wild fish from the cleanest waters can keep your risk level low.
The new research on PCBs and IVF success was presented at the 2010 American Society of Reproductive Medicine conference (ASRM) by Shruthi Mahalingaiah MD from Boston's Brigham and Women's Hospital. The studies highlight how increased exposure to polychlorinated biphenyls (PCBs) can cause higher levels of PCBs in your blood which is closely tied to implantation failure in IVF. Higher exposure levels to PCBs were also associated with reduced live birth rates. Blood levels of a now banned fungicide hexachlorobenzene were also tied to a higher risk of IVF failure.
These new findings are soon to be published and worth taking note if you are trying to conceive. Being careful with your fish consumption could give your chances of IVF success a welcome boost.
Mahalingaiah conducted two further studies to further tease out the connections between; PCBs, hexachlorabenzene, and the pesticides DDT and DDE on IVF outcome. The studies examined data from 765 Boston area women who pursued 827 cycles of IVF, or IVF with ICSI between 1994 and 2003.
The results of this extensive study confirmed that women with the highest levels of PCBs had a far greater risk of implantation failure, and a lower live birth rate than women with low exposure levels.
The mechanism through which PCBs and fungicides reduce IVF success is as yet unknown but PCBs are known to permeate the whole body and and are present within the micro-environment of the ovarian follicles where they may act as hormonal disruptors.
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Mahalingaiah S, et al "Association of polychlorinated biphenyls (PCBs) with adverse reproductive outcomes during in vitro fertilization (IVF)" ASRM 2010; Abstract O-246.
Mahalingaiah S, et al "Association of persistent organic pollutants hexachlorobenzene (HCB), dichlorodiphenyltrichloroethane (DDT), and dichlorodiphenyldichloroethane (DDE) with in vitro fertilization (IVF) outcomes" ASRM 2010; Abstract O-247.
astdr.cdc.gov Agency for toxic substances and disease registry
Medpage Today accessed Dec 6 2010