Exposure to the phytoestrogen genistein prior to conception may adversely affect female fertility and pregnancy outcomes, depending on the dosage and duration of exposure, a new study in mice suggests.
Genistein is an isoflavone found in soy foods and dietary supplements, and, like other plant estrogens, may be consumed by women to relieve menopausal conditions such as hot flashes, weight gain and depression. Chronic preconception exposure to genistein affected pregnancy rates in mice and was associated with prolonged labor, smaller litters and pups, and higher rates of pup mortality, scientists at the University of Illinois report in a paper accepted for publication in the journal Reproductive Toxicology.
The findings add to a growing body of research that raises troubling questions about the potential health risks of long-term exposure to plant-based estrogens. Genistein is among the chemicals that the National Institute of Environmental Health Sciences classifies as endocrine disruptors because they can interfere with bodily systems that are controlled by hormones.
Many women are taking dietary supplements that contain genistein, the researchers said, and there is very little information on its potential effects on reproduction in adult women. Although the findings are preliminary, the researchers said that little is known about the potential effects of long-term phytoestrogen use, and women should be cautious about their exposure, especially if they plan to conceive in the near future.