Most population-based studies agree that infertility affects 15 to 20% of couples. It is the job of the reproductive medicine specialist to determine the unique cause of each couple’s challenge in establishing a healthy pregnancy. While sometimes the answer is quickly uncovered (failure to ovulate, blocked fallopian tubes, or the complete absence of sperm), many patients are faced with the difficult reality that their diagnostic workup has not produced a clear reason for their difficulty becoming pregnant.
This category of “unexplained infertility” is the reason why determining the incidence of male factor infertility is so difficult. We do know that a complete lack of sperm (azoospermia) occurs in 1% of all males and as many as 10-15% of male patients struggling with infertility. Furthermore, we know that a severe deficiency in sperm count (oligozoospermia) is found in as many as 25% of couples battling infertility. Other abnormalities on semen analysis, such as poor motility (the ability of a sperm to swim quickly and in a straight line), and poor morphology (abnormal shape of the sperm) impact many other patients. As a result, a male contribution to infertility is diagnosed in 40-50% of patients who present to the infertility clinic.
However, these numbers come from an era in which the semen analysis was virtually the only available tool for estimating male reproductive function. As we learn more about the biology of sperm, it has become clear that many patients who have normal semen analyses actually suffer from poor sperm function. These more advanced diagnostics, such as DNA fragmentation and sperm epigenetic evaluation, may reveal that many couples who were told that their infertility was “unexplained” may actually have more subtle causes of infertility.
While these tests are still in the early stages of their development, they provide intriguing possibilities to better understand each couple’s challenges and to individualize care. In truth, assigning a diagnosis as “male factor” or “female factor” only helps us create the most effective treatment plan. What our patients really want is focused care that results in a healthy baby. Fortunately, we continue to get closer to our goal of providing an effective strategy to all patients that walk through our door.