What is infertility?

Most experts define infertility as not being able to get pregnant after at least one year of trying. Women who are able to get pregnant but then have repeat miscarriages are also said to be infertile.

Pregnancy is the result of a complex chain of events. In order to get pregnant:

• A woman must release an egg from one of her ovaries (ovulation).
• The egg must go through a fallopian tube toward the uterus (womb).
• A man's sperm must join with (fertilize) the egg along the way.
• The fertilized egg must attach to the inside of the uterus (implantation).

Infertility can result from problems that interfere with any of these steps.

About 12 percent of women (7.3 million) in the United States aged 15-44 had difficulty getting pregnant or carrying a baby to term in 2002, according to the National Center for Health Statistics of the Centers for Disease Control and Prevention.

Is infertility just a woman's problem?

No, infertility is not always a woman's problem. In only about one-third of cases is infertility due to the woman (female factors). In another one third of cases, infertility is due to the man (male factors). The remaining cases are caused by a mixture of male and female factors or by unknown factors.

Infertility in men is most often caused by:

• problems making sperm -- producing too few sperm or none at all
• problems with the sperm's ability to reach the egg and fertilize it -- abnormal sperm shape or structure prevent it from moving correctly

Sometimes a man is born with the problems that affect his sperm. Other times problems start later in life due to illness or injury. For example, cystic fibrosis often causes infertility in men.

What increases a man's risk of infertility?

The number and quality of a man's sperm can be affected by his overall health and lifestyle. Some things that may reduce sperm number and/or quality include:

• alcohol
• drugs
• environmental toxins, including pesticides and lead
• smoking cigarettes
• health problems
• medicines
• radiation treatment and chemotherapy for cancer
• age

What causes infertility in women?

Problems with ovulation account for most cases of infertility in women. Without ovulation, there are no eggs to be fertilized. Some signs that a woman is not ovulating normally include irregular or absent menstrual periods.

Less common causes of fertility problems in women include:

• blocked fallopian tubes due to pelvic inflammatory disease, endometriosis, or surgery for an ectopic pregnancy
• physical problems with the uterus
• uterine fibroids

What things increase a woman's risk of infertility?

Many things can affect a woman's ability to have a baby. These include:

• age
• stress
• poor diet
• athletic training
• being overweight or underweight
• tobacco smoking
• alcohol
• sexually transmitted diseases (STDs)
• health problems that cause hormonal changes

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