Today, with very few exceptions, in the case of moderate or severe male infertility (unless it can be reversed medically or surgically) in vitro fertilization (IVF) with intracytoplasmic sperm injection is the treatment of choice. In such cases, intrauterine insemination (IUI) will, in my opinion, not improve the chance of pregnancy over no treatment at all and accordingly is contraindicated.
The diagnosis of male factor infertility is often based on the results of a simple semen analysis which today, is largely conducted by computer analysis which has replaced the old convention, morbid microscopic, visual evaluation using a Coulter counter. However, while computerized semen analysis has vastly improved the accuracy of assessing sperm count and motility, it is not reliable in evaluating structural sperm defects. To do the latter, we use a grading system known as the Kruger classification. A normal sperm count is one where after several days of abstinence, more than 20 million sperm are present per milliliter of ejaculate. While the sperm count is a helpful tool, it is not the most important parameter. Rather sperm motility and morphology are far more significant measures. When more than 50% of motile sperm are motile and especially if most are moving linearly and purposefully, augers well for male fertility, but a motility of more than 40% is also compatible with adequate male fertility potential. When it comes to the potential to initiate pregnancy through intercourse, a Kruger score of over 14% points to optimal male fertility but when it comes to requirements for optimal IVF outcome, a score of more than 4% is adequate.
While a semen analysis is the most widely used method for assessing male fertility, it lacks both specificity and sensitivity. There are other tests that can augment its reliability. Some of these include sperm chromosomal analyses to look for structural and numerical chromosomal defects; sperm cultures for infection; hormonal testing to determine whether the cause of sperm dysfunction is due to testicular insufficiency is the result of inadequate brain-pituitary stimulation of sperm production, testicular biopsy; testing the ability of sperm to attach to eggs or penetrate its envelopment (the zona pellucida) sperm antibody testing, biochemical testing of the semen, measurement of sperm antibodies (see below) and importantly, the relatively recent introduction of the sperm chromatin structure assay-SCSA (see below).
In cases of absent sperm in the ejaculate (azoospermia) or very low sperm parameters, measurement of blood FSH, LH, testosterone, TSH and prolactin is needed. If the FSH/LH is high (much over 12MIU/ml) then it is likely that this is a testicular failure and probably little could be done to improve matters. On the other hand, if the FSH/LH level is in the normal range, the cause of absent sperm in the ejaculate (azoospermia) could be obstruction of both sperm ducts (vasa deferentia). Confirmation would require a thorough urological exam).