What is Infertility?

Infertility is generally defined as not being able to get pregnant (conceive) after one year (or longer) of unprotected sex.

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.

In general, infertility is defined as not being able to get pregnant (conceive) after one year (or longer) of unprotected sex. Because fertility in women is known to decline steadily with age, some providers evaluate and treat women aged 35 years or older after 6 months of unprotected sex. While these definitions of infertility are used for data collection and monitoring, they are not intended to guide recommendations about the provision of fertility care services. Individuals and couples who are unable to conceive a child should consider making an appointment with a reproductive endocrinologist—a doctor who specializes in managing infertility. Reproductive endocrinologists may also be able to help women with recurrent pregnancy loss, defined as having two or more spontaneous miscarriages.

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

• An egg must be released from one of the ovaries (ovulation).
• Sperm must fertilize the egg.
• The fertilized egg (embryo) must travel from a fallopian tube toward the uterus (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.
• Endometriosis.
• A history of pelvic inflammatory disease
• Known or suspected uterine or tubal disease
• A history of more than one miscarriage
• Genetic or acquired conditions that predispose to diminished ovarian reserve (chemotherapy, radiation)

For men:

• A history of testicular trauma
• Prior hernia surgery
• Prior use of chemotherapy
• A history infertility with another partner
• Sexual dysfunction

Is infertility a common problem?

Yes. In the United States, about 1 in 5 (19%) married women aged 15 to 49 with no prior births in the United States are unable to get pregnant after 1 year of trying. Also, about 1 in 4 (26%) women in this group 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.

What causes infertility in men?

Infertility in men can be caused by different factors, including disruption of testicular or ejaculatory function, hormonal, and genetic disorders, and is typically evaluated by a semen analysis. A specialist will study the volume, number, movement, and shape of the sperm in a semen sample to determine if a male factor is involved.

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.
• Having overweight or obesity.
• Excessive alcohol or drug use (opioids, marijuana).
• A history of trauma to the testes.
• Exposure to testosterone, radiation, certain medicines, or certain environmental toxins.
• Frequent exposure of the testes to high temperatures.
• 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 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 21 to 35 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). PCOS 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, weight loss, or a combination of these factors.
• Improper function of the hypothalamus and pituitary glands. These glands in the brain produce hormones that maintain normal ovarian function.
• Premature ovarian insufficiency (POI). POI, sometimes referred to as premature menopause, occurs when a woman’s ovaries stop producing eggs before she is 40.
• Menopause. 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, including intrauterine adhesions, endometrial polyps, adenomyosis, and congenital anomalies of the uterus.

What increases a woman’s risk of infertility?

• Age. About 1 in 5 (22%) married couples in which the woman is 30-39 have problems conceiving their first child compared to about 1 in 8 (13%) married couples in which the woman is younger than 30. Fertility declines with age primarily because egg quality declines over time. In addition, older women have fewer eggs left and they are more likely to have health conditions that can cause fertility problems. Aging also increases a woman’s chances of miscarriage 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).

How do doctors treat infertility?

Male and female infertility can be treated with medicine, surgery, intrauterine insemination, or assisted reproductive technology (ART).

Doctors recommend specific treatments for infertility based on the factors contributing to infertility, its duration, and the age of the female.

For more information on infertility and ART, please see CDC’s Division of Reproductive Health.