Both the ability to freeze human spermatozoa and the possibility of pregnancy following intrauterine insemination have existed for >40 years. There have been a number of improvements during that time concerning the methods of freezing and thawing human spermatozoa. Initially, the use of the cryoprotective properties of glycerol allowed a major improvement; subsequently, changes were mainly empirical. It was a long time before specific cryobiological studies were undertaken. However, the necessity for these became apparent with the partial recovery or sometimes loss of motility after freezing either subfertile semen before chemotherapy or radiotherapy, or spermatozoa collected from non-physiological situations (epididymal or testicular spermatozoa). The main trends in improvement have defined end-points other than the percentage of motility recovery or the assessment of ultrastructural damage. More sensitive criteria of the objective assessment of motility, energy status, damage to the plasma membrane or to subcellular elements, chromatin stability and chromosomal damage have been proposed as complementary end-points to better assess sperm cryopreservation. A different approach was related to the biochemical environment and physical conditions imposed on spermatozoa during the freezing and thawing process. Biochemical changes were assessed following different combinations of various extenders which attempted either to better preserve some parameter or to avoid the tendency towards drastic increase in osmotic pressure. Analysis of physical conditions was linked to the rate of cooling, freezing and warming, and was based on cryobiological studies. Finally, even though such improvements are not negligible, many questions remain unanswered. The extensive use of frozen spermatozoa during assisted reproductive techniques, together with the development of assisted fertilization using surgically collected spermatozoa, creates the need for additional studies to improve the cryopreservation of human spermatozoa.

Cryopreservation↗

PubMedDate not supplied

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.

Abortion, Habitual↗

PubMedDate not supplied

Follow-up studies of children born after frozen sperm donation.

The need to assess the health of children born after assisted reproductive technologies (ART) using frozen donor spermatozoa has been a major concern for the last decade. Most available published studies are confusing (since they are retrospective) and refer to small numbers of cases or involve a bias. Two prospective and large population-based studies have been published, one in France and the other in Australia. The general characteristics of children born after ART using frozen spermatozoa was unchanged in comparison with the general population (weight, prematurity, stillbirths, sex ratio). However, the rate of multiple pregnancy was increased, first in artificial insemination with donor semen (AID), where the use of hormonal treatment may be too heavily prescribed, and second in IVF with donor semen (IVF/D) where both the ovulation induction treatments and embryo transfer policy increase the rate of multiple pregnancies. As far as birth defects or chromosomal abnormalities are concerned, no difference has been observed from the general population. Finally, the use of frozen spermatozoa does not seem to affect the health of children conceived by AID or IVF/D. The psychosocial development of such infants is not as well known because of the confidentiality in many countries concerning sperm donation. However, the available information on the psychosocial development of these children up to the age of 8-10 years appears to be reassuring. Larger and longer studies are needed to answer such questions, particularly with regard to adulthood.

Birth Weight↗

PubMedDate not supplied

Tail stump spermatozoa: morphogenesis of the defect. An ultrastructural study of sperm and testicular biopsy.

We have studied the ultrastructure of testes biopsies and immotile spermatozoa from a supposed secondary infertile male. A wide range of tail defects has been described in testes and semen. Among these, tail stump spermatozoa occurs rarely. Although the origin of this defect is unknown, testes sections revealed that damage occurs during spermiogenesis at the latest stages during flagellum elongation in spermatids.

Adult↗