Kaiser Daily Reproductive Health Report Wednesday, November 26, 2003 Pregnancy & Childbirth Chemical in Marijuana Could Aid Embryo Implantation in Low Doses, Cause Miscarriages at Higher Levels, Study Says Although low concentrations of the chemical anandamide -- which occurs naturally in the body and is released when marijuana is burned -- plays an important role in embryo implantation, even slightly higher doses may interfere with embryo implantation and cause miscarriage, according to a study published in the Nov. 24 early edition of the Proceedings of the National Academy of Sciences, BBC News reports. Dr. Sudhansu Dey and colleagues at Vanderbilt Medical Center located a chemical pathway in mouse embryos that is triggered by low levels of anandamide. When low levels of the chemical were released, a mechanism in the embryo was turned on that allowed it to implant in the uterus. However, the researchers discovered that if anandamide levels were increased only four-fold, embryo implantation was hindered, according to BBC News (BBC News, 11/25). Dey said that higher anandamide levels have been observed in women who have miscarried, adding that he believes that "at higher levels these molecules may interfere with pregnancy," according to Wired News (Philipkoski, Wired News, 11/24). Dey concluded, "These results are relevant to humans because spontaneous pregnancy losses occur in women with elevated anandamide levels," adding, "This study places the embryo as a target for natural and endocannabinoids (e.g. those from cannabis smoke), and raises the significance of cannabinoid signaling in female fertility," according to BBC News. Professor John Oxford, a toxicologist from Imperial College London, said that the study's results were "very plausible," adding, "We know that cannabinoids affect sperm -- although there's not much objective evidence that it has an effect on female fertility." Oxford added, "It's difficult to carry out a proper controlled trial to find out what is happening" (BBC News, 11/25). Dey said that further study is needed to determine if cannabinoids could be used as a fertility treatment in humans, according to Wired News (Wired News, 11/24). NPR's "Morning Edition" on Tuesday reported on the cannabinoid study. The segment includes comments by Dey; Herbert Schuel, professor of pathology and anatomical sciences at the University at Buffalo-State University of New York; and Fuller Bazer, veterinary physiology and pharmacology professor at Texas A&M University (Palca, "Morning Edition," NPR, 11/25). The segment is available online in RealPlayer. http://www.kaisernetwork.org/daily_reports/rep_index.cfm?DR_ID=21053 Click on the above link to access more links on this study.