Chevy Chase, MD--Researchers in China may have found a method for male contraception that is effective, reversible and without serious short-term adverse effects according to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

"For couples who can not, or prefer not to use only female-oriented contraception, options have been limited to vasectomy, condom and withdrawal," said Dr. Yi-Qun Gu, MD, of the National Research Institute for Family Planning in Beijing, China. "Our study shows a male hormonal contraceptive regimen may be a potential, novel and workable alternative."

Dr. Gu said this study is the largest multi-center, male hormonal contraceptive efficacy clinical trial of an androgen preparation in the world. Participants included 1,045 healthy fertile Chinese men aged 20-45 years. Each participant had fathered at least one child within the two years before the study and had a normal medical history. Their female partners were between 18 and 38 years of age and had normal reproductive function.

Males were injected monthly with 500 mg of a formulation of testosterone undecanoate (TU) in tea seed oil for thirty months. Results showed a cumulative contraceptive failure (pregnancy) rate of 1.1 per 100 men in the 24-month efficacy phase. No serious adverse events were reported and reproductive function returned to the normal fertile reference range in all but two participants.

"Despite the present encouraging results, the long-term safety of this hormonal male contraceptive regimen requires more extensive testing with a focus on cardiovascular, prostate and behavioral safety," said Dr. Gu.

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Other researchers working on the study include Xiaowei Lang of the National Research Institute for Family Planning in Beijing, China; Weixiong Wu of Guangzhou Institute for Population and Family Planning in Guangzhou, China; Minli Liu of Guizhou Institute for Population and Family Planning in Guiyang, China; Shuxiu Song of Hebei Research Institute for Family Planning in Shijiazhuang, China; Lifa Cheng and Liwei Bo of Henan Research Institute for Population and Family Planning in Zhengzhou, China; Chengliang Xiong of Tongji Medical College in Wuhan, China; Xinghai Wang of Jiangsu Family Planning Research Institute in Nanjing, China; Xiaozhang Liu of Sichuan Family Planning Research Institute in Chengdu, China; Lin Peng of Yunnan Family Planning Research Institute in Kunming, China; and Kangshou Yao of Zhejiang Institute of Planned Parenthood in Hangzhou, China.

The article "Multicenter Contraceptive Efficacy Trial of Injectable Testosterone Undecanoate in Chinese Men," will appear in the June 2009 issue of JCEM.

Founded in 1916, The Endocrine Society is the world's oldest, largest, and most active organization devoted to research on hormones, and the clinical practice of endocrinology. Today, The Endocrine Society's membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 100 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Maryland. To learn more about the Society, and the field of endocrinology, visit our web site at www.endo-society.org.