In Vitro Fertilization
MICHELLE A. MULLEN
A common clinical standard describes the male factor as significant when a couple fails to conceive naturally and repeat semen analysis demonstrates one or more of the following: concentration of sperm cells less than 20 million per milliliter, progressive forward motility less than 50 percent, or greater than 50 percent abnormal forms. Natural pregnancies may occur when the analysis of semen shows poor results, and infertility may persist when semen parameters are near normal. What is clear is that oligozoospermia (very few sperm cells) is highly associated with infertility, and azoospermia (no sperm cells) is absolutely associated with infertility (true sterility).
The causes of male-factor infertility or subfertility are poorly understood. Primary testicular dysfunction may be caused by disease of the testes as a result of infection, trauma, serious medical illness, genetic abnormality, radiation, or chemical toxicity from drugs or environmental agents such as pesticides. Hypothalamic or pituitary disease may also contribute to subfertility in the male. Medical management of male infertility may involve surgical repair of varicocele, administration of luteinizing hormone, or administration of antibiotics. The extremely limited results of these interventions in most cases have led to increasing interest in the application of IVF (in vitro fertilization and variants such as GIFT) for