What is Infertility?

For couples hoping to become parents, difficulty conceiving a baby can be frustrating and unexpected. Many couples who struggle with infertility do end up having children, sometimes with medical help. An important early step is understanding possible causes of infertility.

Infertility is generally defined as not being able to get pregnant after 1 year of unprotected sex. Most experts recommend visiting a fertility specialist at this point. Because fertility in women is known to decline steadily with age, women who are 35 or older may consider seeking evaluation and treatment after 6 months of trying. Couples with infertility should consider making an appointment with a reproductive endocrinologist—a doctor who specializes in managing infertility.

Image of a couple looking despondently at a pregnancy test

Infertility is generally defined as not being able to get pregnant after 1 year of unprotected sex.

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Pregnancy is the result of a process that has many steps. To get pregnant:

An egg must be released from one of the ovaries (ovulationexternal icon).
Sperm must fertilize the egg.
The fertilized egg (embryo) must travel from a fallopian tubeexternal icon toward the uterusexternal icon (womb).
The embryo must attach to the inside of the uterus (implantation).

Infertility may result from a problem with any or several of these steps.

Couples with the following conditions, signs, or symptoms should not delay seeing their health care provider when they are trying to become pregnant:

For women:

Irregular menstrual periods or no periods.
Very painful periods.
Endometriosisexternal icon.
Pelvic inflammatory disease.
A history of more than one miscarriage.

For men:

Suspected male factor infertility (e.g. history of testicular trauma, hernia surgery, chemotherapy, or infertility with another partner).

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Is infertility a common problem?

Yes. About 7% of married women aged 15 to 44 in the United States are unable to get pregnant after 1 year of trying. Also, about 12% of women aged 15 to 44 have difficulty getting pregnant or carrying a pregnancy to term.

Though it is often thought of as a woman’s problem, infertility can affect both men and women. In about 35% of couples with infertility, a male factor is found with or without a female factor. In about 8% of couples with infertility, a male factor is the only cause found.

What causes infertility in men?

A specialist will study the movement, shape, and number of sperm in a semen sample to determine if a male factor is involved.

Some risk factors for abnormal semen include:

Disruption of testicular or ejaculatory function, such as through trauma to the testes, heavy alcohol or drug use, cancer treatment, use of certain medicines, or medical disorders.
Hormonal disorders caused by improper function of the hypothalamus or pituitary glands, which maintain normal testicular function.
Genetic disorders such as Klinefelter’s syndrome, Y-chromosome microdeletion, myotonic dystrophy, or other, less common genetic disorders.

What increases a man’s risk of infertility?

Couples in which the male partner is 40 or older are more likely to report difficulty conceiving.
Being overweight or obese.
Excessive alcohol use.
Exposure to testosterone, radiation, certain medicines, or certain environmental toxins.
Frequent exposure of the testes to high temperatures.

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What causes infertility in women?

Women need functioning ovaries, fallopian tubes, and a uterus to get pregnant. Conditions affecting any one of these organs can contribute to female infertility. Some of these conditions are listed below and can be evaluated with tests.

Disruption of ovarian function and effects of ovarian “age”

A woman’s menstrual cycle is, on average, 28 days. Regular, predictable periods that occur every 24 to 32 days mean that the woman is likely to be ovulating. A woman with irregular periods may not be ovulating. Not ovulating can be caused by the following:

Polycystic ovary syndrome (PCOS).external iconPCOS is a condition that causes women to not ovulate or to ovulate irregularly. PCOS is the most common cause of female infertility.
Diminished ovarian reserve (DOR). Women are born with all the eggs they will have in their lifetime, and the egg count naturally decreases over time. DOR is a condition in which there are fewer eggs remaining in the ovaries than normal.

Functional hypothalamic amenorrhea (FHA). Women with FHA do not get their periods because of excessive exercise, stress, or low body weight.
Improper function of the hypothalamus and pituitary glands. These glands in the brain produce hormones that maintain normal ovarian function.
Premature ovarian insufficiencyexternal icon (POI). POI, sometimes referred to as premature menopause, occurs when a woman’s ovaries stop producing eggs before she is 40.
Menopause.external icon Menopause is a natural decline in ovarian function that usually occurs around age 50. By definition, a woman in menopause has not had a period in 1 year.

Fallopian tube obstruction

Risk factors for blocked fallopian tubes can include a history of pelvic infection, ruptured appendix, gonorrhea or chlamydia, endometriosis, or abdominal surgery.

Physical characteristics of the uterus

Depending on a woman’s symptoms, the uterus may be evaluated by transvaginal ultrasound to look for fibroids or other problems.

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What increases a woman’s risk of infertility?

Age. About 1 in 6 couples in which the woman is 35 and older have fertility problems. Aging decreases fertility because older women have fewer eggs left, the eggs are less healthy, and the woman is more likely to have health conditions that can cause fertility problems. Aging also increases a woman’s chances of miscarriageexternal icon and of having a child with a genetic abnormality.
Smoking.
Excessive alcohol use.
Extreme weight gain or loss.
Excessive physical or emotional stress that results in amenorrhea (not having periods).