Current Issues & Treatment Strategies for Male Infertility
Printer-friendly versionby Peter T. K. Chan MD, CM, MSc, FRCS(C)
Summer 2007
Introduction
Recent statistics have demonstrated that up to 11% of couples have difficulties conceiving. The female partners often are the ones taking an active role in seeking fertility management, as indicated by the disproportionately higher frequency of initial fertility consultations to gynecologists, whether it is initiated by the female partners or by their primary care physicians, rather than to a urologist. While various cultural and social norms have led the public to assume that fertility is primarily a "female issue", the reality is that only about a third of fertility problems in couples are due to pure female-factor, while another third is due to pure male-factor and another third a combination of both male- and female-factors. Thus male-factor infertility is found in over half of all cases of couples experiencing infertility. In recent years, the medical profession has begun to put more emphasis on the importance of male-factor infertility, both in its diagnosis and management. The purpose of this article is to provide an update on some of the new issues regarding male infertility and how you can go about getting help with male-factor infertility.
Current state of fertility management Are more men becoming infertile?
Various reasons have been proposed to explain the rising incidence of male-factor infertility. Some investigators believe that such an increase simply reflects the increase in the availability of reproductive centers combined with an increased awareness of infertility and acceptance in the use of assisted reproductive technologies. However, a study in 1992 indicated that human sperm density in semen worldwide has declined appreciably by 1% per year during the period from 1938 to 1990. Various investigators criticized the poor or highly variable data, incorrect statistical analysis or changes in study populations included in the study that might explain the trend reported. Others have supported the findings reported despite the potentially large random error. Surely, further investigations are required to resolve the controversy of whether men are becoming more infertile and, if so, the exact causes of this observation.
Aging and male fertility
Other investigators blame the social trend toward delaying parenthood until later in life, resulting in a more significant impact of aging on the reproductive status of men. Indeed, compared to the 1970s, there is a 50% increase in birth rate for fathers over the age of 35. Reasons for such a delay in fathering children are numerous, including various social reasons such as other priorities in life, improved overall quality of life in aging men, improved treatment satisfaction of sexual dysfunction and, as seen above, increase in the availability and acceptance of assisted reproductive technologies.
While the impact of aging on female reproductive system is well known, it is not until recently that researchers begin to understand the mechanism of the "male biological clock". As men age, there is a decline in the activity and co-ordination of the hypothalamus-pituitary-testes axis, resulting in a decrease in the release of gonadotropin releasing hormone, and a decrease in the circadian release of luteinizing hormone and serum testosterone level. In addition, semen volume, sperm motility and percentage of sperm with normal morphology have all been reported to decline as men age, resulting in a lower pregnancy rate and increased time to pregnancy.
This decline of reproductive status in men, however, is not nearly as sharp as in women at menopause and most men can still father genetic children even at an advanced age. Unfortunately, this "aging father" phenomenon is frequently highlighted when it occurs to celebrities, with better-known examples including Tony Randall, Michael Douglas, David Letterman, Charlie Chaplin and Jack Nicholson. These stories inadvertently de-emphasize the importance of the potential negative impact of aging on male fertility.
In addition to the quantitative and qualitative decline in reproductive function in aging men, the recent evidence on the decline of the genetic integrity of sperm is more concerning. The percentage of sperm with abnormal chromosome numbers and structure increases from about 3% in men below the age of 35 to over 14% in men above the age of 45. Using advanced molecular genetic tests to evaluate sperm nuclear chromatin structure, studies have confirmed a significantly higher percentage of sperm with lower genetic quality from men older than 35. These sperm with damaged genetic integrity may either fail to achieve fertilization or, if successful, result in anomalies in embryo development. Furthermore, various hereditary conditions, including Down’s syndrome, schizophrenia, hemophilia A, Duchene muscular dystrophy and autism, have been shown to increase in children as the paternal age increases. Taken together, there is compelling evidence pointing at suboptimal reproductive outcomes when delaying having children until more advanced ages.
Environmental and other factors affecting male fertility
There is an increasing number of studies worldwide reporting an association of various environmental contaminants with reproductive disorders. Indeed, various environmental contaminants may negatively affect the human reproductive system depending on the duration, timing (intra-utero, childhood, adolescence or adulthood) and level of exposure.
Tobacco smoking has long been associated with male infertility and sub-fertility. Tobacco smoke may represent one of the most common chemical toxins that humans are exposed to through active and passive smoking. Tobacco smoking can result in more time required to achieve pregnancy, decreased sperm count, motility, sperm morphology and anomalies in sperm chromosomes. The fertilizing ability of sperm has been shown to decrease with tobacco consumption. The success rates of assisted reproductive technologies have also been shown to decrease in couples who are exposed to smoking.
Occupational exposure to various chemicals represents another environmental risk that can have a negative impact on fertility. A wide range of organic solvents in hair-styling products, paints and mechanical grease may result in adverse reproductive outcomes. Exposure to contemporary-use pesticides has been associated with an increased proportion of abnormal sperm. Excess heat in the working environment has been shown to affect testicular function, resulting in abnormal semen parameters. Interestingly, a recent investigation suggested that the common practice of using a portable computer on the lap with the heated battery in the bottom of the computer being in proximal contact to the testes may generate excessive heat, particularly with prolonged usage of the computer, and may increase the risks of testicular dysfunction.
Industrial and technological advances have led to the production and use of many compounds that have been shown to have a negative impact on male fertility. Many of these contaminants affect the normal reproductive function by acting as "endocrine disruptors" that interfere with normal hormonal physiology in reproduction. One of the better-studied examples is "phthalate", a chemical that is primarily used as a plasticicizer in the manufacture of flexible vinyl, which in turn is found in various consumer products such as floor tiles, wall coverings, food containers and even medical devices. Other forms of phthalates may also be used in the production of personal-care products such as perfumes, lotions and cosmetics. The ubiquitous use of phthalates results in human exposure via dietary ingestion, dermal absorption and inhalation. Various investigators have raised concerns about the association of phthalate exposure with poor semen quality, although epidemiological data is currently limited.
What can be done for male factor infertility?
The diagnosis and management of male factor infertility have undergone tremendous changes in the past decade. The following are some suggestions that all men planning on having children should consider:
1) Try to minimize the delay in having a family
As we have discussed previously, aging has a significant negative impact on reproductive outcomes. Thus, the current trend of putting off family-forming until later in life for the sake of other social or career agendas may have a tremendous impact in some men. The goals of achieving success in establishing a family and excelling in a career should thus be carefully balanced.
2) Maintain a healthy lifestyle
Regular and moderate levels of exercise, a balanced diet, avoidance of exogenous toxins such as tobacco, recreational drugs, industrial and environmental toxicants, stress reduction and minimization of excessive heat exposure to the reproductive organs are among the means men should employ to prepare themselves for fatherhood.
3) Know your risks
Various conditions may put you at risk for infertility. Congenital conditions such as undescended testes (cryptorchidism), mumps with associated inflammation of the testes (orchitis), childhood hernia or other scrotal surgeries and varicoceles, if present, will put you at risk of experiencing infertility. In addition, acquired conditions such as epididymo-orchitis, sexually transmitted diseases, prostate disorders, scrotal and inguinal surgeries or injuries, and cancers (especially when chemotherapy or radiation therapies to the pelvis were used), are among the conditions that can affect fertility. Patients with these conditions should thus seek evaluation of fertility early on to ensure that proper management can be implemented promptly.
4) Get tested early
Evaluation of male fertility is much simpler than evaluation of female fertility. In addition to a thorough history and physical examination by the doctor, basic laboratory evaluation for men includes a morning blood test for hormonal profile (testosterone, follicle-stimulating hormone and others) and semen analyses. Based on the results of these tests, additional tests may be arranged to fully evaluate the fertility status of the man.
5) Do your homework and find out what treatments are best for you and your partner
If you suffer from male factor infertility, do not panic or despair. Many conditions that lead to male infertility, once diagnosed, can be treated to improve your chance of having children. Treatment may involve medication, surgery, or simply changes in lifestyle (see above). Once the semen profile is optimized, if you still have difficulties in achieving pregnancy with your partner, assisted reproductive technologies may be used. As there are many treatment options available to help you to have children depending your fertility status, you should discuss with your reproductive health providers the details of the treatment plan. Feel free to read up on the various books and information materials from reputable sources that can give you additional valuable information. Various websites and patient support groups can also be helpful to help you and your partner understand the fertility options you have. If you have any questions about the materials or information you came across in your own research, talk to your doctors. They are in the best position to provide advice to help you to achieve the goal of having healthy children.
About the author
Peter T. K. Chan MD, CM, MSc, FRCS(C) is the Director of Male Reproductive Medicine at the McGill University Health Center. After completing his Urology residency at McGill, he received his fellowship training in Male Infertility and Microsurgery at the Cornell University and a fellowship in Molecular Genetics at the Population Council of Rockefeller University.
Dr. Chan has received numerous national and international awards for his research in men’s health. He is the youngest recipient in the history of McGill University for the prestigious Everett C. Reid Award of Excellence in Teaching in Urology.
Dr. Chan has published over 50 professional journal articles, book chapters and videos. He has recently launched a book entitled "Reproductive Medicine Secrets" and is currently the Principal Investigator of two research projects funded by the Canadian Institute for Health Research. He is also featured in "Doctorology", a television documentary produced by the Discovery Channel on the various medical subspecialties.
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