The patient's Guide to Infertility
Dr. Oberlin's Infertility Basics
Male infertility refers to a male's inability to cause pregnancy in a fertile female. In humans it accounts for 40–50% of infertility. It affects approximately 7% of all men. Male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity.
Testicular factors
Testicular factors refer to conditions where the testes produce sperm of low quantity and/or poor quality despite adequate hormonal support and include:
Varicocele, is a condition of swollen testicle veins. It is present in 15% of normal men and in about 40% of infertile men. It is present in up to 35% of cases of primary infertility and 69-81% of secondary infertility.
Age (see also: Paternal age effect)
Genetic defects on the Y chromosomeY chromosome microdeletions
Abnormal set of chromosomesKlinefelter syndrome
Idiopathic failure
Defects in USP26 in some cases
Acrosomal defects affecting egg penetration
Idiopathic oligospermia - unexplained sperm deficiencies account for 30% of male infertility.
Pre-testicular causes
Pre-testicular factors refer to conditions that impede adequate support of the testes and include situations of poor hormonal support and poor general health including:
Hypogonadotropic hypogonadism due to various causesObesity increases the risk of hypogonadotropic hypogonadism. Animal models indicate that obesity causes leptin insensitivity in the hypothalamus, leading to decreased Kiss1 expression, which, in turn, alters the release of gonadotropin-releasing hormone (GnRH).
Undiagnosed and untreated coeliac disease (CD). Coeliac men may have reversible infertility. Nevertheless, CD can present with several non-gastrointestinal symptoms that can involve nearly any organ system, even in the absence of gastrointestinal symptoms. Thus, the diagnosis may be missed, leading to a risk of long-term complications. In men, CD can reduce semen quality and cause immature secondary sex characteristics, hypogonadism and hyperprolactinaemia, which causes impotence and loss of libido. The giving of gluten free diet and correction of deficient dietary elements can lead to a return of fertility. It is likely that an effective evaluation for infertility would best include assessment for underlying celiac disease, both in men and women.
Strenuous riding (bicycle riding, horseback riding)
Medications, including those that affect spermatogenesis such as chemotherapy, anabolic steroids, cimetidine, spironolactone; those that decrease FSH levels such as phenytoin; those that decrease sperm motility such as sulfasalazine and nitrofurantoin
Genetic abnormalities such as a Robertsonian translocation
Tobacco smoking
There is increasing evidence that the harmful products of tobacco smoking may damage the testicles and kill sperm, but their effect on male fertility is not clear. Some governments require manufacturers to put warnings on packets. Smoking tobacco increases intake of cadmium, because the tobacco plant absorbs the metal. Cadmium, being chemically similar to zinc, may replace zinc in the DNA polymerase, which plays a critical role in sperm production. Zinc replaced by cadmium in DNA polymerase can be particularly damaging to the testes.
DNA damage
Common inherited variants in genes that encode enzymes employed in DNA mismatch repair are associated with increased risk of sperm DNA damage and male infertility. As men age there is a consistent decline in semen quality, and this decline appears to be due to DNA damage. The damage manifests by DNA fragmentation and by the increased susceptibility to denaturation upon exposure to heat or acid, the features characteristic of apoptosis of somatic cells.[26] These findings suggest that DNA damage is an important factor in male infertility.
Epigenetic
An increasing amount of recent evidence has been recorded documenting abnormal sperm DNA methylation in association with abnormal semen parameters and male infertility.
Post-testicular causes
Post-testicular factors decrease male fertility due to conditions that affect the male genital system after testicular sperm production and include defects of the genital tract as well as problems in ejaculation:
Vas deferens obstruction
Lack of Vas deferens, often related to genetic markers for cystic fibrosis
Infection, e.g. prostatitis
Diagnosis
If you or your partner suffer from infertility and live in the Bay Area including Berkeley and Oakland, schedule a consultation with Doctor Daniel Oberlin for evaluation. The diagnosis of infertility begins with a medical history and physical exam. Typically two separate semen analyses will be required. Additional blood tests to look for hormone imbalances, medical conditions, or genetic issues are often utilized.