Infertility & Reproduction Health Center

Tools & Resources

Select An Article

Font Size

Understanding Infertility: The Basics

Infertility is defined as the inability for a couple to become pregnant after a year of regular, unprotected intercourse. The male partner, the female partner, or both, may have a fertility problem. In women over 35 years old, an evaluation and possible treatment is needed after 6 months of unprotected intercourse.

A person who is infertile has a reduced ability to have a child. It usually doesn't mean a person is sterile -- that is, physically unable ever to have a child. Up to 15% of all couples are infertile, but only 1% to 2% are sterile. Half of couples who seek help can eventually bear a child, either on their own or with medical assistance.

Men and women are equally likely to have a fertility problem. In about one in five infertile couples, both partners have contributing problems, and in about 15% of couples, no cause is found after all tests have been done. This is called "unexplained infertility."

For many couples, infertility is a crisis. Fertility problems often come with feelings of guilt or inadequacy. But a diagnosis of infertility is not necessarily a verdict of sterility.

From Egg to Embryo: See the Conception Process

What Causes Fertility Problems in Men?

In men, the most common reasons for infertility are sperm disorders, including:

Low sperm count. Too few or no spermatozoa in the semen.
Low sperm motility. Sperm don't move as well as they should.
Malformation of the sperm.
Blocked sperm ducts.

Another common problem is a temporary drop in sperm production. This happens when the testicles have been injured, such as when the testicles have been too hot for too long or the man has been exposed to chemicals or medications that affect sperm production.

Spending a long time in a hot tub, for example, or wearing underwear that holds the testicles too close to the body, can increase the temperature in the testicles and impair sperm production. Sometimes there is a physical reason. In the relatively common condition called varicocele, veins around the vas deferens (the duct that carries sperm from testicle to urethra) becomes dilated -- similar to a varicose vein in the leg. The pooling of blood in these veins keeps the temperature inside the scrotum too high.

Certain lifestyles, like increased alcohol intake and smoking, can also have a negative effect on sperm count. Age, too, is a factor: Men 40 years and older have decreased fertility.

What Causes Fertility Problems in Women?

The primary reason for infertility in women is anovulation, or lack of ovulation (release of eggs from the ovary). The major cause of anovulation is a condition called polycystic ovary disease, or PCOS.

Another reason for female infertility is the inability of the fallopian tubes to carry eggs from the ovary to the uterus, usually due to scar tissue that may have resulted from prior infection or from a condition called endometriosis.

1 | 2

Next Page >

WebMD Medical Reference