The effect of male factors in repeated spontaneous abortion: lesson from in-vitro fertilization and intracytoplasmic sperm injection.

Between 6.5 and 21% of pregnancies result in spontaneous abortion. The incidence of repeated spontaneous abortion (RSA) is, however, lower: 0.05-1.0% of pregnancies. These values vary, not only according to the populations studied and the means of diagnosing the miscarriages, but also to the age and the parity of the patient: 4% at 20 years of age versus 16% after 35 years. These differences are greater if biochemical pregnancies are taken into account. The aetiologies of RSA are multiple and at times even multifactorial. While certain aetiologies, such as chromosomal, anatomic, hormonal, immunological or unexplained anomalies, have been extensively explored, the sperm characteristics likely to influence the quality of the conceptus have rarely been examined. This review examines the male factor's contribution in RSA.