Infertility is the inability to naturally conceive a child or to carry a pregnancy to full term. There are many reasons why a couple may not be able to conceive, or may not be able to conceive without medical assistance. (Note: although some aspects of this article may be generalizable, it deals primarily with infertility as pertains to human couples.)

Definition

Reproductive endocrinologists, the doctors specializing in infertility, consider a couple to be infertile if:

• the couple has not conceived after 12 months of unprotected intercourse if the female is under the age of 35
• the couple has not conceived after 6 months of unprotected intercourse if the female is over the age of 35 (declining egg quality of females over the age of 35 account for the age-based discrepency as when to seek medical intervention)
• the female is incapabile of carrying a pregnancy to term.

Infertility affects approximately 10% of people of reproductive age [1] 15% of couples. Roughly 40% of cases involve a male contribution or factor, 40% involve a female factor, and the remainder involve both sexes.

Healthy couples in their mid-20s having regular sex have a one-in-four chance of getting pregnant in any given month. This is called "Fecundity". There are some health insurance companies that cover diagnosis of infertility but frequently once diagnosed will not cover any treatment costs.

Male infertility

Factors relating to male infertility include[3]:

• Pretesticular causes
  • Endocrine problems, i.e. diabetes mellitus, thyroid disorders
  • Hypothalamic disorders, i.e. Kallmann syndrome
  • Hyperprolactinemia
  • Hypopituitarism
  • Hypogonadism due to various causes
  • Drugs, alcohol
• Testicular factors
  • Genetic defects on the Y chromosome
    • Y chromosome microdeletions
  • Abnormal set of chromosomes
    • Klinefelter syndrome
  • Neoplasm, e.g. seminoma
  • Idiopathic failure
  • Cryptorchidism
  • Varicocele
  • Trauma
  • Hydrocele
  • Mumps
  • Testicular dysgenesis syndrome
• Posttesticular causes
  • Vas deferens obstruction
  • Infection, e.g. prostatitis
  • Retrograde ejaculation
  • Hypospadias
  • Impotence
  • Acrosomal defect/egg penetration defect
• Smoking
  • According to a study conducted by the American Society for Reproductive Medicine, smoking is one the most prominent factors contributing to low sperm count in men.[citation needed]

Some causes of male infertility can be determined by analysis of the ejaculate, which contains the sperm. The analysis includes counting the number of sperm and measuring their motility under a microscope:

• Producing few sperm, oligospermia, or no sperm, azoospermia.
• A sample of sperm that is normal in number but shows poor motility, or asthenozoospermia.

In the majority of cases of male infertility and low sperm quality, no clear cause can be identified with current diagnostic methods. It has been speculated that random mutations of the Y chromosome may be an important factor. As the human Y chromosome is passed directly from father to son, it is not protected against accumulating copying errors, whereas other chromosomes are error corrected by recombining genetic information from mother and father. This may leave natural selection as the primary repair mechanism for the Y chromosome. Microdeletions in the Y chromosome have been found at a much higher rate in infertile men than in fertile controls and the correlation found may still go up as improved genetic testing techniques for the Y chromosome are developed. (Existing test kits for Y chromosome microdeletions with PCR markers cover only a tiny fraction of the chromosome's 23 million base pairs and therefore very likely still miss most mutations. The gold standard test for genetic mutation, namely complete DNA sequencing of a patient's Y chromosome, is still far too expensive for use in epidemiologic research or even clinical diagnostics.)

Combined infertility

In some cases, both the man and woman may be infertile or sub-fertile, and the couple's infertility arises from the combination of these conditions. In other cases, the cause is suspected to be immunological or genetic; it may be that each partner is independently fertile but the couple cannot conceive together without assistance.

Unexplained infertility

In about 15% of cases the infertility investigation will show no abnormalities. In these cases abnormalities are likely to be present but not detected by current methods. Possible problems could be that the egg is not released at the optimum time for fertilization, that it may not enter the fallopian tube, sperm may not be able to reach the egg, fertilization may fail to occur, transport of the zygote may be disturbed, or implantation fails. It is increasingly recognized that egg quality is of critical importance and women of advanced maternal age have eggs of reduced capacity for normal and successful fertilization.

The history should include prior testicular (penis) insults (torsion, cryptorchidism, trauma), infections (mumps orchitis, epididymitis), environmental factors (excessive heat, radiation, chemotherapy), medications (anabolic steroids, cimetidine, and spironolactone may affect spermatogenesis; phenytoin may lower FSH; sulfasalazine and nitrofurantoin affect sperm motility), and drugs (alcohol, marijuana). Sexual habits, frequency and timing of intercourse, use of lubricants, and each partner's previous fertility experiences are important. Loss of libido and headaches or visual disturbances may indicate a pituitary tumor. The past medical or surgical history may reveal thyroid or liver disease (abnormalities of spermatogenesis), diabetic neuropathy (retrograde ejaculation), radical pelvic or retroperitoneal surgery (absent seminal emission secondary to sympathetic nerve injury), or hernia repair (damage to the vas deferens or testicular blood supply).

The diagnosis of infertility begins with a medical history and physical exam. The provider may order blood tests to look for hormone imbalances or disease. A semen sample may be needed. The volume of the semen is measured, as well as the number of sperm in the sample. How well the sperm move is also assessed.

The cornerstone of the male partner evaluation is the history. It should note the duration of infertility, earlier pregnancies with present or past partners, and whether there was previous difficulty with conception.

A complete examination of the infertile male is important to identify general health issues associated with infertility. For example, the patient should be adequately virilized; signs of decreased body hair or gynecomastia may suggest androgen deficiency.

The scrotal contents should be carefully palpated with the patient standing. As it is often psychologically uncomfortable for young men to be examined, one helpful hint is to make the examination as efficient and as matter of fact as possible.

The peritesticular area should also be examined. Irregularities of the epididymis, located posterior-lateral to the testis, include induration, tenderness, or cysts.

Prevention & Expectations

Some cases of male infertility may be avoided by doing the following:

• Avoid drugs and medications known to cause fertility problems, like steriods and some antifungal medications.
• Avoid excessive exercise.
• Avoid exposure to environmental hazards such as pesticides.
• Avoid frequent hot baths or use of hot tubs.
• Avoid tight underwear or pants.
• Eat a diet with adequate folic acid, and vitamine C and Zinc loaded food.
• Get early treatment for sexually transmitted diseases.
• Have regular physical examinations to detect early signs of infections or abnormalities.
• Keep diseases, such as diabetes and hypothyroidism, under control.
• Practice safer sex to avoid sexually transmitted diseases.
• Take a lycopene supplement.
• Wear protection over the scrotum during athletic activities.