Selection of high fertility donors for artificial insemination programmes

One hundred and seventy-seven semen donors were used in an artificial insemination service using frozen semen over a 4 year period. Although the donors were selected for good semen quality, pregnancy rates varied markedly from less than five to greater than 20 pregnancies per 100 treatment cycles. When the characteristics of the 25 most fertile and 25 least fertile donors were compared, only sperm morphology was significantly different. Sperm concentration and motility before and after thawing of semen were similar in the two groups as were the proportions of adverse prognostic factors in the recipients. It is concluded that using more stringent criteria for selection of donors on the basis of sperm morphology and discarding donors who do not produce pregnancies within 12 cycles should improve overall pregnancy rates.