{"id":4315,"date":"2015-05-05T16:20:52","date_gmt":"2015-05-05T21:20:52","guid":{"rendered":"http:\/\/blogs.edf.org\/health\/?p=4315"},"modified":"2016-04-25T10:26:22","modified_gmt":"2016-04-25T15:26:22","slug":"evidence-grows-linking-dehp-exposure-to-reproductive-toxicity-what-is-the-state-of-regulation","status":"publish","type":"post","link":"https:\/\/blogs.edf.org\/health\/2015\/05\/05\/evidence-grows-linking-dehp-exposure-to-reproductive-toxicity-what-is-the-state-of-regulation\/","title":{"rendered":"Evidence grows linking DEHP exposure to reproductive toxicity: What is the state of regulation?"},"content":{"rendered":"

Lindsay McCormick <\/em><\/a>is a Research Analyst.<\/em><\/p>\n

Phthalates are chemical plasticizers found in a wide array of industrial and consumer products, including polyvinyl chloride (PVC) piping and tubing, cosmetics, medical devices, plastic toys, and food contact materials.\u00a0 Because phthalates are often not strongly chemically bound to these products, they can leach out of those products and into the environment<\/a> around us. Given this, it may not be surprising that phthalates and their metabolites can be measured in the bodies<\/a> of nearly all people tested.<\/p>\n

This post reports on important new research on DEHP and summarizes the state of regulation of the chemical in the U.S. and abroad. \u00a0<\/p>\n

Evidence from laboratory experiments where animals are dosed with phthalates strongly suggests that these chemicals have adverse effects on the male reproductive system. The National Research Council (NRC) concluded in its 2008 report<\/a> that male rats prenatally exposed to certain phthalates during a critical developmental window of sexual differentiation are prone to a number of reproductive tract abnormalities; further, the NRC concluded that it is \u201cbiologically plausible\u201d that similar effects may occur in humans exposed to certain phthalates in the womb.<\/p>\n

Now, a study<\/a> conducted by Swan et al. and published in February in the journal of Human Reproduction<\/em> corroborates this hypothesis of effects in humans for one phthalate: diethylhexyl phthalate (DEHP).<\/p>\n

In this study, the largest of its kind, researchers recruited pregnant women from prenatal clinics in San Francisco, Minneapolis, Rochester (NY), and Seattle and measured phthalate levels excreted in the urine during the first trimester of pregnancy. To assess the potential impact on reproductive health, the researchers measured anogenital distance (AGD) \u2013 the distance between the anus and the genitals \u2013 in the infants immediately after birth. AGD is an indicator of prenatal exposure to androgen (a male sex hormone), with typical AGDs being 50-100% longer in males than in females. Shorter AGD is a well-established marker for disruption of male genital tract development (or \u201cfeminization\u201d), and has been associated with reduced fertility<\/a> in males.<\/p>\n

This study found that AGD was significantly shorter in male infants whose mothers were more highly exposed to DEHP during their first trimester of pregnancy. No association between prenatal exposure to phthalates and AGD was found in female infants.<\/p>\n

A well-designed study<\/em><\/strong><\/p>\n

The Swan et al. study is not the first to suggest that prenatal phthalate exposure in males may impact their ability to reproduce as adults, as measured by AGD (for example, see here<\/a> and here<\/a>). However, it arguably provides the most robust evidence to date of such effects in humans.\u00a0 According to the authors, this study is \u201cfar more powerful and precise\u201d than any other study that has previously investigated this question. \u00a0Some of the strengths of this study include:<\/p>\n