What Causes Infertility?

Infertility is technically defined as 12 months of properly timed intercourse without conception.  In reality, most people do not wait 12 months before seeking assistance from a health care professional.  The truth is, especially in women greater than 35, 12 months is too long to wait before beginning a fertility evaluation. 

While a fertility evaluation needs to consider a wide variety of potentially complicated diagnosis, it is best understood when we break the causes of infertility into broad categories:

• Male

•         Ejaculation/ Sperm Factor

• Female

•         Ovulation/ Egg Factor
•         Fallopian Tube Factor
•         Uterine Factor

• Unexplained

Male Factor

Male factors are generally related to the quantity or quality of sperm.  Sperm is evaluated with a semen analysis, which checks 4 primary characteristics;

1.       Volume of ejaculated fluid (greater than 2 ml)

2.       Concentration of sperm in the ejaculate (at least 20 million sperm per ml of ejaculate)

3.       Motility of sperm (at least 40% sperm moving well)

4.       Morphology of sperm (8-14% of sperm should be perfectly shaped, this is the most subjective characteristic and will vary from lab to lab)

Female Factor

The female reproductive system plays a greater role in the logistics of fertility; therefore, there are more potential factors which need to be explored if conception does not occur. 

1.       Ovulation is the monthly release of an egg from the ovary.  It is usually followed, 2 weeks later, by menstruation or a positive pregnancy test.  Women who do not normally menstruate, often times, are not normally ovulating.  Women who have regular periods are usually ovulating.

2.       Egg factors include abnormalities with the quantity or quality of eggs.  This factor is intimately related to a woman’s age and is evaluated through a variety of blood tests as well as ultrasound and medical history.  Both the quantity and quality of eggs diminish as a woman ages.

3.       The Fallopian tubes are the conduits which permit sperm and egg to meet and thus fertilization to occur. An obstruction in the Fallopian tubes which prevent the sperm and egg from coming together is a relatively common cause of infertility.

4.       Abnormalities in the uterus due to trauma, infection, congenital irregularities like a septum or acquired pathology such as fibroids can all contribute to infertility.  A physical exam, transvaginal ultrasound and HSG or MRI can usually diagnose most uterine factors.

Unexplained infertility describes the situation when testing for all of the above factors is normal, but conception still does not occur.  This diagnosis can be very frustrating because most people want to understand why pregnancy is not occurring.  Fortunately, using an empiric treatment plan, many couples with unexplained infertility can successfully conceive.

If you have questions about infertility or any of the factors above, feel free to contract us, one of our doctors would be happy to speak with you.