Abortion rate in A.I.D. and semen characteristics: a study of 1345 pregnancies.

A study undertaken on 1345 pregnancies resulting from artificial insemination with donor showed an 18% risk of abortion. This figure is the same as that admitted for natural reproduction. It does not depend on any of the classically studied semen characteristics and in particular remains invariant whatever the postthaw motility, the factor most strongly linked to conception rate. Two results, well known from the literature, i.e. the increased abortion rate mentioned in natural reproduction when the sperm is of poor quality and the high incidence of repeated abortions when sperm quality is particularly good are discussed. The first of these results cannot be considered as being established in a statistically significant way. The second may result from different sources of bias, some of which are identified. In essence a high frequency of abortions signifies simply a high frequency of pregnancies, it is therefore not surprising that the semen is in this case particularly good.