Study Examines Impact of Phthalates on Infant Genital Development

Submitted by UCSF Urology on December 6, 2012 at 9:22 am

Image of toddlerPhthalates, chemicals that soften plastics, are widely used in food packaging, medical devices and personal care products. Scientists are concerned that phthalates may pose a health risk because they can disrupt the function of androgen and other sex hormones and have been linked to urogenital abnormalities in animal studies.

UCSF is collaborating with four other sites on a National Institutes of Health-funded study to determine whether phthalates affect urogenital development in human infants. The Infant Development and Environmental Study (TIDES) will attempt to correlate maternal phthalate levels with the development of reproductive organs in infant boys and girls. The study will follow participating women through three trimesters of pregnancy and record information about the urogenital development of their newborns shortly after birth, says Sarah Janssen, MD, PhD, MPH, director of TIDES at UCSF. Janssen holds academic appointments in Urology and Occupational and Environmental Medicine at UCSF. She and UCSF Pediatric Urology Chief Laurence Baskin, MD, are working closely on this study.

Approximately 1,200 infants will be included in TIDES, once data are gathered from UCSF and the other study sites: the University of Rochester School of Medicine, New York; Seattle Children’s Hospital and University of Washington School of Medicine; and the University of Minnesota. The study is being coordinated through the Mt. Sinai School of Medicine under principal investigator Shanna Swan, PhD.

As part of the study, researchers hope to establish a simple, reliable method of measuring anogenital distance (AGD) and determine the average length of this measurement in male and female infants. AGD is a standard measure used in toxicology to detect anti-androgen activity. In animal studies, the male AGD is twice the length of the female AGD, said Janssen, but the average length for human males and females has never been established. Rat models show that AGD is shorter in the male offspring of pregnant animals exposed to bis(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP), the two phthalates that will be measured in this study.

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