London, 8 July 2013: Studies over the past 20 years have suggested (though not unequivocally confirmed) that semen quality is in decline, reflected most evidently in falling sperm counts and reduced sperm motility.(1) The explanations have been controversially attributed to environmental factors (such as exposure to toxins) and to male smoking. Now, a new study based on a 20-year follow-up of one of the world's largest study cohorts, suggests that exposure to several factors in utero and in early life may also lead to reduced semen parameters in adulthood - and potentially to a decline in male fertility.
The study, which found that adverse fetal growth, exposure to maternal smoking, and a lower childhood growth trajectory were all associated with a subsequent decline in testicular function, is reported today at the annual meeting of ESHRE by Roger Hart, Professor of Reproductive Medicine at the University of Western Australia and medical director of Fertility Specialists of Western Australia in Perth.
The study was based on follow-up of the Western Australian Pregnancy (Raine) Cohort, which began in 1989-91 with the enrolment of 2900 mothers during pregnancy; their babies had regular assessment from birth, which included fetal growth measurements. Part of the 20-year follow-up of this cohort (in 423 of the men at the age of 20-22 years) involved a testicular assessment, which included measurement of testicular volume, analysis of semen quality and hormone production - as well as body composition for fat distribution.
Results showed that around one in six of the men tested had sperm parameters below the "normal" threshold recently defined by the World Health Organization (WHO). That is:
|Contact: Christine Bauquis|
European Society of Human Reproduction and Embryology