Male Fertility / Infertility

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What can cause male infertility?

Male fertility can be impacted by many factors including obesityprescription medicationstobaccoalcohol, marijuana, radiation, and environmental toxins.  Additionally, age, genetics, varicocele, hormonal causes, sexual dysfunction, infection, previous surgery to the pelvic/groin area, past fertility history, or systemic illnesses (such as cancer) may contribute to infertility.  Because of the many factors that may affect male infertility a coordinated effort is required for couples trying to have children.

Male Infertility Evaluation

How often does male infertility occur?

One of every five couples seeks treatment for infertility, and in up to 50% of cases, the male partner is identified to be a cause of infertility.  Male infertility can occur due to many causes, including genital defects, sperm transport blockage, erection and ejaculation failure, deficient sperm production and function, surgery, and toxic or environmental exposures.

Why is semen analysis important when diagnosing male fertility issues?

Male infertility may occur when there are abnormalities in sperm identified by abnormal semen analysis testing.  Semen analysis describes sperm count, sperm concentration, sperm shape (morphology), sperm movement (motility), acidity (pH), and quantity (volume).  Normal reference values are defined by the World Health Organization (WHO) criteria and include total sperm count of 39 million sperm per ejaculate, sperm concentration of 15 million/ml, 40% total motility, 4% morphologically normal, 1.5 ml volume.

Semen analysis WHO 2010 values

Sperm Count/Concentration:

What are oligospermia and azoospermia?

Infertility may occur may occur above these values or when there is decreased sperm number (oligospermia, <15-20 million sperm per milliliter), decreased quality of sperm (abnormal shape, movement, sperm DNA), or complete absence of sperm (azoospermia).

Low (or no)  sperm count can result from varicoceles, hormonal/genetic abnormalities, medications, or systemic diseases such as cancer.   Oligospermia (low sperm count) can have many causes, often unknown, and is usually identified along with abnormalities in the sperm (movement, shape, or DNA issues).  Azoospermia (no sperm in the ejaculate) is identified in 15% of infertile men.  There are two general categories which explain the cause of having decreased or no sperm in the ejaculate: obstructive azoospermia (OA, 40% of all cases of azoospermia) and non-obstructive azoospermia (NOA) which includes the rest of men with azoospermia.  These are exactly what they sound like: obstructive azoospermia (OA) results from a blockage along the genital tract somewhere between the testicle (where sperm are produced) and the ejaculatory duct (where the semen enters the urethra during ejaculation) to leave the body.  Other parts of the genital tract can also be blocked (the technical names include the rete testis, efferent ducts, epididymis (sperm maturation takes place here), vas deferens, and ejaculatory duct). Non-obstructive azoospermia (NOA) involves impairment or absence of sperm production (spermatogenesis) due to a variety of causes.

For more detail see our posts on specifics of obstructive azoospermia and non-obstructive azoospermia.


If the volume of ejaculate is low, this might reflect inadequate collection of the specimen or obstruction of the male reproductive tract (blocked plumbing system) such as ejaculatory duct obstruction.


Movement of the sperm reflects sperm that are alive and healthy.  If sperm are moving slowly or not at all, there may be an engine problem (issue with the sperm in terms of energy or overall health).  Decreased motility can occur with varicocele, medications, systemic illness, or antisperm antibodies.


Abnormal shape of sperm may represent something additional problems with sperm such as DNA issues (DNA fragmentation).  Abnormal sperm shape may be the consequence of heat or other environmental influences (such as a varicocele).  Although the relationship between poor morphology and pregnancy by intercourse, IUI or IVF remains unclear, there is recent research indicating that abnormally low morphology does not impact intrauterine insemination or IVF/ICSI results.


With obstruction of the ejaculatory ducts or congenital bilateral absence of the vas deferens (CBAVD), there is acidic (low) semen pH.   About 50-70% of the seminal fluid in humans originates from the seminal vesicles, which is normally with high pH (basic).  The female reproductive tract is slightly acidic, so the basic pH of the seminal vesicle secretion balances this condition.  When the seminal vesicles are blocked, the ejaculate becomes acidic.  

We are pleased to discuss male infertility workup further with you.  Please contact us for additional information and to schedule a consultation.

Please continue reading for more details about obstructive azoospermia or non-obstructive azoospermia.

Key points:
  • Male infertility (also called male factor infertility) is involved in up to 50% of cases among infertile couples.
  • Male fertility is affected by many factors including genetics, medications, environmental toxins, and prior surgery (vasectomy or hernia repair).
  • Semen analysis is a key component of the male infertility workup and helps to better identify sperm issues such as abnormal number, movement, or shape.
  • At CMHR of Connecticut, medical or surgical treatment plans for male infertility may be an option depending on semen analysis, lab and or imaging findings.
Matthew Wosnitzer, M.D.