Monitoring reproductive health in Europe: what are the best indicators?

The Reprostat Steering Committee asks for the best monitors of reproductive health. In many European countries, some deleterious agents have caused declines over the past half-century in both dizygotic (DZ) twinning rates and sperm counts. No strong evidence suggests that these declines have reversed, though they may have ceased in some countries. Here attention is only directed at potential secular changes in the proximate biological determinants of fertility (ovulation, coitus, semen quality, fertilization, spontaneous fetal loss and 'dead time'). The most comprehensive biological monitor of reproductive health is the 'natural' DZ twinning rate (viz the rate of DZ twinning in the absence of any medical intervention around the time of conception). At present, natural DZ twins are augmented by twins produced by new techniques. So efforts should be made to estimate the annual numbers of these iatrogenic twins in each European country. Then it would be possible to follow the movements of each national natural DZ twinning rate, and thus to continue monitoring a useful measure of reproductive health that has been available in most European countries for many years. Efforts should be made to assess the sperm quality of volunteer donors in each European country.