Environment Plays Important Role In Reproduction- Study Of Wild Baboons Provides Insight For Human Infertility Treatment

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Julie Rathbun, UNIVERSITY OF WASHINGTON
Health Sciences/Medical Affairs
News & Community Relations
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July 26, 1996

Environment plays important role in reproduction -- study of wild baboons provides insight for human infertility treatment

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FOR IMMEDIATE RELEASE -- Seasonal conditions and social stresses have a significant impact on reproduction in wild baboons, a finding that may offer new hope for the thousands of American women affected by infertility.

"Understanding how and why reproductive failure occurs in nature provides a whole new way of thinking about infertility treatment," said Dr. Samuel Wasser, assistant professor of obstetrics and gynecology at the University of Washington School of Medicine. "Future diagnosis and treatment of infertility in women may, accordingly, place greater emphasis on identifying and reducing life stresses."

Results of a two-year study by Wasser appear in the July issue of Biology of Reproduction.

In his study, Wasser measured reproductive hormone levels in fecal samples of 30 free-ranging yellow baboons at Mikumi National Park in Tanzania to distinguish between conceptive and nonconceptive cycles. These results indicated females required less progesterone to conceive when of high social status and during the optimal season of the year when ecological conditions promoting offspring survival were best (abundant food and water and low risk of predation at weaning time). Wasser explains the physiological mechanisms related to this increased conception under predictably good conditions seems to be an increase in the density of receptors binding progesterone, eliciting its biological action.

While baboons of high social status conceived more frequently, Wasser also found they experienced higher rates of spontaneous abortion. Wasser notes the same physiological mechanisms which make conception easier when environmental predictors of offspring survival are good may also allow some conceptions to occur that would not normally be successful.

"Environmental changes, including sustained psychosocial or physical stress may play a much larger role in conception than previously thought," said Wasser, noting that the reproductive physiology in the baboon is more similar to humans than any other mammal. "By predicting which stresses affect reproduction, infertility treatments can be tailored to reduce such stresses and their physiological consequences."

Further research will focus on the development of psychosocial and endocrine therapies for human patients to see if a reduction of environmental stress and/or certain combinations of hormone supplements can positively affect reproduction.

Wasser, who serves as scientific director of Seattle's Woodland Park Zoo Center for Wildlife Conservation, is director of a 22-year ongoing study of wild baboons in southeastern Tanzania. His research was supported by grants from the H.F. Guggenheim Foundation, the National Geographic Society, the Smithsonian Institution, the National Science Foundation and the National Institute of Mental Health.