Obtained pregnancies by AID using frozen semen in relation to specific qualities of the semen

The results obtained by insemination with 3,418 frozen donor ejaculates with known semen characteristics were analyzed. The concentrations of motile spermatozoa before and after thawing were significantly higher in samples from donors producing pregnancies compared to samples from donors not causing pregnancies. In ejaculates known specifically to have caused a pregnancy even higher concentrations were found. It was assumed that the concentration of motile spermatozoa after thawing was the most important parameter, and by dividing the material into fractions it could be demonstrated that a spermatozoa concentration of more than 20 million/ml is essential for reasonable results.