Health Illustrated Encyclopedia



Infertility is the inability to become pregnant after 12 months of unprotected sex (intercourse).

Alternative Names

Barren; Inability to conceive; Unable to get pregnant


Primary infertility is the term used to describe a couple that has never been able to achieve a pregnancy after at least 1 year of unprotected sex.

Secondary infertility describes couples who have been pregnant at least once, but have not been able to achieve a pregnancy again.

Causes of infertility include a wide range of physical and emotional factors. About 30 - 40% of all infertility is due to a "male" factor such as:

Some factors that affect sperm count are:

  • Heavy marijuana use
  • Use of prescription drugs such as cimetidine, spironolactone, and nitrofurantoin

"Female" factor causes include:

  • Abnormal egg transport from the ovaries through the fallopian tubes (causes 40 - 50% of infertility in couples)
  • Hormone imbalance
  • Ovarian cysts
  • Pelvic infection
  • Poor nutrition
  • Problem with ovulation
  • Scarring from sexually transmitted disease or endometriosis
  • Tumor

The other 10 - 30% of infertility cases may be caused by factors from both partners, or no cause that can be identified.

About 10 - 20% of couples will be unable to conceive after 1 year of trying to become pregnant. It is important that you try to get pregnant for at least 1 year.

The chances for a pregnancy in healthy couples who are both under the age of 30 and having sex regularly is only 25 - 30% per month. A woman's peak fertility occurs in her early 20s. As a woman ages beyond 35 (and especially after age 40), the likelihood of getting pregnant drops to less than 10% per month.

In addition to age-related factors, other infertility risks include:


  • A range of emotions by either or both members of the couple. In general, such reactions are greater among childless couples. Having at least one child tends to soften these painful emotions.
  • Inability to become pregnant.

Exams and Tests

A complete history and physical examination of both partners is essential.

Tests may include:


Treatment depends on the cause of infertility. It may involve:

  • Education and counseling
  • Medical procedures such as in vitro fertilization
  • Medicines to treat infections and clotting disorders, or promote ovulation

It is important to recognize and discuss the emotional impact that infertility has on you and your partner, and to seek medical advice from your health care provider.

Support Groups

Many organizations provide informal support and referrals for professional counseling. See infertility - support group.

Outlook (Prognosis)

A cause can be determined for about 85 - 90% of infertile couples.

Getting the right therapy (not including advanced techniques such as in vitro fertilization) allows pregnancy to occur in 50 - 60% of couples who were infertile.

Without any treatment, 15 - 20% of couples diagnosed as infertile will eventually become pregnant.

Possible Complications

Although infertility itself does not cause physical illness, it can have a major emotional impact on the couples and individuals it affects.

Couples may have problems with their marriage. Individuals may experience depression and anxiety.

When to Contact a Medical Professional

Call for an appointment with your health care provider if you are unable to get pregnant.


Because sexually transmitted diseases (STDs) often cause infertility, practicing safer sex behaviors may minimize the risk. Gonorrhea and chlamydia are the two most common causes of STD-related infertility.

STDs often don't have symptoms at first, until PID or salpingitis develops. These conditions scar the fallopian tubes and lead to decreased fertility, infertility, or an increased risk of ectopic pregnancy.

Getting a mumps vaccine in men has been shown to prevent mumps and its complication, orchitis. The vaccine prevents mumps-related sterility.

Some forms of birth control, such as the intrauterine device (IUD), carry a higher risk for future infertility. IUDs are not recommended for women who have not already had a child.

If you are considering getting an IUD, carefully weigh the increased risk of infertility and the potential benefits with your partner and health care provider.

Getting diagnosed and treated early for endometriosis may decrease the risk of infertility.


Speroff L, Fitz M. Clinical Gynecologic Endocrinology and Infertility. 7th ed. Lippincott Williams & Wilkins; 2004.

Stenchever A, et al. Comprehensive Gynecology. 4th ed. St. Louis, Mo: Mosby; 2001:1204-1206.

Provided by

Review Date: 12/29/2008
Reviewed By: Susan Storck, MD, FACOG, Chief, Eastside Department of Obstetrics and Gynecology, Group Health Cooperative of Puget Sound, Redmond, Washington; Clinical Teaching Faculty, Department of Obstetrics and Gynecology, University of Washington School of Medicine. Previously reviewed by Peter Chen, MD, Department of Obstetrics & Gynecology, University of Pennsylvania Medical Center, Philadelphia, PA; and David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. (2/5/2008)
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