But it is no guarantee of safety, study authors say.
According to a March 25 story in the Canadian Press (CP), researchers have documented the presence of prion proteins in the fertility drugs used by some 300,000 women in Canada and the United States every year in an effort to conceive. Fertility drugs are purified through a process that involves the urine of postmenopausal women.
Prion proteins are found naturally in the body and in their normal state are considered harmless. However, researchers say it is possible for these proteins to alter their configuration in spontaneous fashion. As a result of this transformation, the proteins can become infectious.
Co-author of the study is Dr. Neil Cashman, the scientific director of PrioNet Canada who holds a Canada research chair in neurodegeneration at the University of British Columbia (UBC). He stressed in the CP report that no evidence of CJD was found in any of the samples studied, nor have there been any adverse reports from the field.
"There has never been a single recognized case of Creutzfeldt-Jakob disease in a woman who received these urinary pharmaceuticals," he stressed. "So that's a good thing. It means it's not common, if there is transmission. ... So if there's a risk, it's an extremely small one."
For the study, researchers examined dozens of urine-derived drug samples from various pharmaceutical companies and batches, and found evidence of prion proteins.
The suggestion is that the drugs carry a previously unrecognized risk of contamination with the infectious agents.
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"This does not mean that every woman in Canada that's had these drugs is going to get sick, or even a small proportion of them," Pierson said. "But we need to look."
The study was published in the Public Library of Science (PLoS) ONE.