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This article waslast modified on December 4, 2020.
What is infertility?

Infertility is the inability to get pregnant (conceive). It is typically diagnosed after a couple has tried to get pregnant for 12 months without success. Infertility may also be diagnosed when a woman has been able to get pregnant but has been unable to carry a fetus to term (miscarried).

Infertility affects about 10-15% of couples in the United States. About one-third of cases are due to women's problems with fertility, another third are due to men's problems, and the remaining are due to a combination of men's and women's infertility issues.

Fertility depends on the successful timing and interaction of many factors. Hormones produced by glands, including the hypothalamus, pituitary, and thyroid glands, as well as by a woman's ovaries and a man's testicles play an important role in controlling and supporting reproduction.

In order for a successful pregnancy to occur, a woman must develop and release an egg from one of her ovaries. Women are born with a fixed number of eggs (oocytes), each of which is contained in a fluid-filled cavity in the ovaries called a follicle. At birth, there are 1-2 million follicles; however, by the time of puberty, most have degenerated, leaving about 200,000 to 400,000 follicles. Throughout a woman's reproductive years, the few hundred thousand available eggs will be further reduced in number with a total of about 400 mature eggs released, about one per month.

After a woman's menstrual cycle begins, follicle-stimulating hormone (FSH) causes several follicles to mature; however, usually only one will dominate. During this time, estradiol production increases, peaking at day 14 of a typical 28-day cycle, causing the uterine lining to thicken and stimulate the production of the hormones gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and FSH. The combined effects of these hormones result in the release of an egg from a mature follicle, initiating the process of ovulation.

Once released, the egg travels through the fallopian tube and is fertilized by a man's sperm, forming an embryo, which moves into the uterus and implants within the thickened uterine lining (endometrium). As the embryo grows, the placenta forms, nourishing and supporting the fetus throughout the gestation period. Problems with infertility can be associated with any one or more of these processes. Some of the causes of infertility are easy to identify and fix, while others are more complex.

Accordion Title
About Infertility
  • Causes

    Age plays an important role in fertility, particularly since many couples have postponed childbearing until their 30's and 40's.

    • Peak fertility in a woman occurs in her early 20's and declines substantially by age 35 and even more so after age 40. By the time a woman reaches menopause, few if any eggs may be available or functional.
    • As a man ages, the number of sperm decreases, along with sperm motility, thus reducing the chances of pregnancy occurring. Other age-related problems include low testosterone and prostate, erectile, or ejaculation problems.

    Besides age, other factors that can affect fertility in both women and men include:

    • Underlying medical conditions, such as diabetes
    • Unhealthy lifestyle or habits, such as smoking, use of alcohol and/or drugs
    • Being very overweight or underweight
    • Exposure to chemicals or toxins
    • Excessive exercise

    Although precise causes of infertility are sometimes unknown, there are certain problems common to people affected by it. Conditions may affect the release of eggs (ovulation), interfere with sperm movement, or affect fertilization or implantation of a fertilized egg, to name a few general examples.

    In women, infertility may be caused by conditions such as:

    In men, infertility may be caused by conditions such as:

    • Erectile dysfunction, a common cause, affecting 10 to 20 million American men
    • Problems with sperm, such as a low sperm count, poor sperm movement (motility), clumped or agglutinated sperm that are unable to swim to the egg and abnormally shaped sperm
    • An imbalance of hormones, such as testosterone, LH, and FSH
    • Enlarged veins around the testicles (varicoceles)
    • Obstructions that prevent sperm from being released during ejaculation
    • Mumps infection, which can cause inflammation of the testicles
    • Injury to one or both testicles
    • Acute illness or prolonged fever
    • Exposure of the testicles to excessive heat
    • Klinefelter syndrome

    Infertility testing can be complex, expensive, and time-consuming, and often both partners may be required to undergo extensive physical examinations, blood tests, lifestyle evaluations, and/or imaging procedures (for example, ultrasound) to determine the cause.

  • Tests

    Tests for Women

    Initial evaluation of a woman's fertility includes a personal and family history along with a thorough physical examination. Several tests can be used to help diagnose any issues and aid in treatment. An evaluation often begins with determining whether and when a woman is ovulating.

    At-home Ovulation Prediction
    There are three types of at-home methods useful for predicting ovulation.

    • Ovulation predictor kits are the most accurate of the three methods. The test detects an increased level of luteinizing hormone (LH) present in an early morning urine sample 1 to 2 days before ovulation.
    • Basal body temperature (BBT) can be measured at home using a special thermometer that specifically measures temperature between 96o and 100o F to help predict the most fertile days in a woman's monthly menstrual cycle when ovulation occurs. Basal body temperature (taken before getting out of bed) decreases just before ovulation and rises at ovulation, remaining elevated for up to 3 days. If the cycle is charted for 3 to 4 months, a pattern can be recognized and intercourse can be timed accordingly. Though sperm have been shown to remain functional in women's reproductive tracts up to 5 days, the most fertile period is 48 hours prior to ovulation. The BBT method is not 100% reliable, but it is simple and inexpensive.
    • Self-examination of vaginal discharge is another method to predict ovulation but is also subject to error. Prior to ovulation, the mucus is stretchy, clear, thin, and slippery, a necessary environment for the survival and transport of sperm. When mucus can be stretched between the thumb and index finger into a thin strand 2 to 3 inches long, ovulation is about to occur and a woman is entering her most fertile period. If a thin layer is placed on a glass slide, a fern-like appearance is present during ovulation (this is called the fern test). Post ovulation, no fern-like appearance will be present because the mucus becomes too thick and less conducive to sperm survival.

    Laboratory Tests
    Blood tests that measure the levels of various hormones can aid in determining causes of infertility. Examples include:

    Because changes in pituitary or thyroid function can also affect the menstrual cycle and ovulation, blood tests that measure thyroid function (TSH and/or free T4) and steroids, such as testosterone and DHEA-S, are also informative as high levels of androgens can contribute to infertility.

    Imaging Procedures
    Imaging techniques may be used to determine physical problems preventing proper fertilization or maintenance of a normal pregnancy. Fiber-optic endoscopy, x-rays, and ultrasound sonograms are used to detect abnormal growths (such as fibroids, polyps, abscesses, tumors), scarring (adhesions) of the uterine walls, and infections.

    Tests for Men

    For men, an evaluation of infertility includes a medical history and physical examination to detect any anatomic abnormalities. In some cases, examination using trans-rectal ultrasound (TRUS) can be used to identify specific abnormalities, such as obstructions blocking the sperm from being released during ejaculation. Absence of sperm (azoospermia) can also be due to missing vas deferens or seminal vesicles.

    Laboratory Tests

    Semen analysis—this is the primary test for infertility in men. Collection and prompt evaluation of a sample of semen can help determine whether there are any defects in the number, shape, and movement (motility) of sperm.

    Blood tests can be used to evaluate hormone levels such as:

    In some instances, a biopsy of testicular tissue can identify infertility problems such as sperm production, abnormal growths, tumors, or underdeveloped reproductive organs.

  • Treatment

    Treatment for infertility depends on a number of factors, including how long the couple has been trying to become pregnant, the age and health of the couple, the cause of infertility, and the couple's preferences about infertility treatments.

    The process can begin with a visit to a gynecologist/obstetrician, urologist specializing in infertility (andrology), reproductive endocrinologist (certified infertility specialist), or fertility clinic. A fertility treatment plan, involving both the man and woman, may include changes in nutrition, lifestyle, and environmental factors.

    Not all cases of infertility can be resolved, but 85% to 90% of cases can be successfully treated using conventional medical therapies, according to the National Institutes of Health. Depending on the problem and diagnosis, one or more of the following treatments may be used:

    • Medications, such as drug therapies to improve a man's sperm count or fertility drugs to stimulate a woman to ovulate
    • Surgery—for example, in men, to remove a blockage that is preventing sperm moving through ducts and tubes or, in women, to remove growths in the uterus called polyps or fibroids
    • Intra-uterine insemination (IUI)—placing sperm directly in a woman's reproductive tract at or near the time of ovulation
    • Assisted reproductive technologies (ART)—these procedures involve handling the egg and sperm in the laboratory and the inserting the fertilized egg (ovum) back into the woman's uterus. A common example is in vitro fertilization (IVF). See the Related Content section for links to more information on these.
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