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. Women with infertility 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:

• A woman’s body must release an egg from one of her ovaries.
• A man’s sperm must join with the egg along the way (fertilize).
• The fertilized egg must go through a fallopian 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.

Impaired fecundity is a condition related to infertility and refers to women who have difficulty getting pregnant or carrying a pregnancy to term.

Yes. In the United States, among heterosexual women aged 15 to 49 years with no prior births, about 1 in 5 (19%) are unable to get pregnant after one year of trying (infertility). Also, about 1 in 4 (26%) women in this group have difficulty getting pregnant or carrying a pregnancy to term (impaired fecundity).

Infertility and impaired fecundity are less common among women with one or more prior births. In this group, about 6% of married women aged 15 to 49 years are unable to get pregnant after one year of trying and 14% have difficulty getting pregnant or carrying a pregnancy to term.

Women need functioning ovaries, fallopian, 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 using several different tests.

Disruption of ovarian function (presence or absence of ovulation and effects of ovarian “age”)

A woman’s menstrual cycle is, on average, 28 days long. Day 1 is defined as the first day of “full flow.” Regular predictable periods that occur every 21 to 35 days likely reflect ovulation. A woman with irregular periods is likely not ovulating.

Ovulation can be predicted by using an ovulation predictor kit and can be confirmed by a blood test to check the woman’s progesterone level on day 21 of her menstrual cycle. Although several tests exist to evaluate a woman’s ovarian function, no single test is a perfect predictor of fertility. The most commonly used markers of ovarian function include follicle-stimulating hormone (FSH) value on day 3 to 5 of the menstrual cycle, anti-müllerian hormone value (AMH), and antral follicle count (AFC) using a transvaginal ultrasound.

Disruption in ovarian function may be caused by several conditions and warrants an evaluation by a doctor.

When a woman doesn’t ovulate during a menstrual cycle, it’s called anovulation. Potential causes of anovulation include the following

• Polycystic ovary syndrome (PCOS). PCOS is a condition that causes women to not ovulate, or to ovulate irregularly. Some women with PCOS have elevated levels of testosterone, which can cause acne and excess hair growth. PCOS is the most common cause of female infertility.
• Diminished ovarian reserve (DOR). Women are born with all of the eggs that they will ever have, and the number of eggs declines naturally over time. DOR is a condition in which there are fewer eggs remaining in the ovaries than expected for a given age. It may occur due to congenital (condition present at birth), medical, surgical, or unexplained causes. Women with DOR may be able to conceive naturally, but will produce fewer eggs in response to fertility treatments.
• Functional hypothalamic amenorrhea (FHA). FHA is a condition caused by excessive exercise, weight loss, stress, or often a combination of these factors. It is sometimes associated with eating disorders such as anorexia.
• Improper function of the hypothalamus and pituitary glands. The hypothalamus and pituitary glands in the brain produce hormones that maintain normal ovarian function. Production of too much of the hormone prolactin by the pituitary gland (often as the result of a benign pituitary gland tumor), or improper function of the hypothalamus or pituitary gland, may cause a woman not to ovulate.
• Premature ovarian insufficiency (POI). POI, sometimes referred to as premature menopause, occurs when a woman’s ovaries fail before she is 40 years of age. Although certain exposures, such as chemotherapy or pelvic radiation therapy, and certain medical conditions may cause POI, the cause is often unexplained. About 5% to 10% of women with POI conceive naturally and have a normal pregnancy.
• 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 for at least one year. Many women experience hot flashes, mood changes, difficulty sleeping, and other symptoms as well.

Fallopian tube obstruction (whether fallopian tubes are open, blocked, or swollen)

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

Fallopian tubes may be evaluated by hysterosalpingogram or by chromopertubation.

• Hysterosalpingogram is an X-ray of the uterus and fallopian tubes. A radiologist injects dye into the uterus through the cervix and simultaneously takes X-ray pictures to see if the dye moves freely through fallopian tubes indicating they are open.
• Chromopertubation is similar to a hysterosalpingogram but is done in the operating room at the time of a laparoscopy. Blue-colored dye is passed through the cervix into the uterus and through the fallopian tubes. This test is used to evaluate if the fallopian tubes are open and to assess if they are dilated.

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. A sonohystogram or hysteroscopy may also be performed to further evaluate the uterine environment.