Causes

An ectopic pregnancy occurs when a pregnancy starts outside the womb (uterus). The most common site for an ectopic pregnancy is within one of the tubes through which the egg passes from the ovary to the uterus (fallopian tube). However, in rare cases, ectopic pregnancies can occur in the ovary, stomach area, or cervix.

An ectopic pregnancy is often caused by a condition that blocks or slows the movement of a fertilized egg through the fallopian tube to the uterus. This may be caused by a physical blockage in the tube by hormonal factors and by other factors, such as smoking.

Most cases of scarring are caused by:

• Past ectopic pregnancy
• Past infection in the fallopian tubes
• Surgery of the fallopian tubes

Up to 50% of women who have ectopic pregnancies have had swelling (inflammation) of the fallopian tubes (salpingitis) or pelvic inflammatory disease (PID).

Some ectopic pregnancies can be due to:

• Birth defects of the fallopian tubes
• Complications of a ruptured appendix
• Endometriosis
• Scarring caused by previous pelvic surgery

The following may also increase the risk of ectopic pregnancy:

• Age over 35
• Having had many sexual partners
• In vitro fertilization

In a few cases, the cause is unknown.

Sometimes, a woman will become pregnant after having her tubes tied (tubal sterilization). Ectopic pregnancies are more likely to occur 2 or more years after the procedure, rather than right after it. In the first year after sterilization, only about 6% of pregnancies will be ectopic, but most pregnancies that occur 2 - 3 years after tubal sterilization will be ectopic.

Ectopic pregnancy is also more likely in women who have:

• Had surgery to reverse tubal sterilization in order to become pregnant
• Had an intrauterine device (IUD) and became pregnant (very unlikely when IUDs are in place)

Ectopic pregnancies occur in 1 in every 40 to 1 in every 100 pregnancies.

Symptoms

• Abnormal vaginal bleeding
• Amenorrhea
• Breast tenderness
• Low back pain
• Mild cramping on one side of the pelvis
• Nausea
• Pain in the lower abdomen or pelvic area

If the area of the abnormal pregnancy ruptures and bleeds, symptoms may get worse. They may include:

• Feeling faint or actually fainting
• Intense pressure in the rectum
• Pain that is felt in the shoulder area
• Severe, sharp, and sudden pain in the lower abdomen

Internal bleeding due to a rupture may lead to low blood pressure and fainting in around 1 out of 10 women.

Exams and Tests

The health care provider will do a pelvic exam, which may show tenderness in the pelvic area.

Tests that may be done include:

• Culdocentesis
• Hematocrit
• Pregnancy test
• Quantitative HCG blood test
• Serum progesterone level
• Transvaginal ultrasound or pregnancy ultrasound
• White blood count

A rise in quantitative HCG levels may help tell a normal (intrauterine) pregnancy from an ectopic pregnancy. Women with high levels should have a vaginal ultrasound to identify a normal pregnancy.

Other tests may be used to confirm the diagnosis, such as:

• D and C
• Laparoscopy
• Laparotomy

Treatment

Ectopic pregnancies cannot continue to birth (term). The developing cells must be removed to save the mother's life.

You will need emergency medical help if the area of the ectopic pregnancy breaks open (ruptures). Rupture can lead to shock, an emergency condition. Treatment for shock may include:

• Blood transfusion
• Fluids given through a vein
• Keeping warm
• Oxygen
• Raising the legs

If there is a rupture, surgery (laparotomy) is done to stop blood loss. This surgery is also done to:

• Confirm an ectopic pregnancy
• Remove the abnormal pregnancy
• Repair any tissue damage

In some cases, the doctor may have to remove the fallopian tube.

A minilaparotomy and laparoscopy are the most common surgical treatments for an ectopic pregnancy that has not ruptured. If the doctor does not think a rupture will occur, you may be given a medicine called methotrexate and monitored. You may have blood tests and liver function tests.

Outlook (Prognosis)

One-third of women who have had one ectopic pregnancy are later able to have a baby. A repeated ectopic pregnancy may occur in one-third of women. Some women do not become pregnant again.

The likelihood of a successful pregnancy depends on:

• The woman's age
• Whether she has already had children
• Why the first ectopic pregnancy occurred

The rate of death due to an ectopic pregnancy in the United States has dropped in the last 30 years to less than 0.1%.

Possible Complications

The most common complication is rupture with internal bleeding that leads to shock. Death from rupture is rare.

When to Contact a Medical Professional

If you have symptoms of ectopic pregnancy (especially lower abdominal pain or abnormal vaginal bleeding), call your health care provider. You can have an ectopic pregnancy if you are able to get pregnant (fertile) and are sexually active, even if you use birth control.

Prevention

Most forms of ectopic pregnancy that occur outside the fallopian tubes are probably not preventable. However, a tubal pregnancy (the most common type of ectopic pregnancy) may be prevented in some cases by avoiding conditions that might scar the fallopian tubes.

The following may reduce your risk:

• Avoiding risk factors for pelvic inflammatory disease (PID) such as having many sexual partners, having sex without a condom, and getting sexually transmitted diseases (STDs)
• Early diagnosis and treatment of STDs
• Early diagnosis and treatment of salpingitis and PID
• Stopping smoking

Alternative Names

Tubal pregnancy; Cervical pregnancy; Abdominal pregnancy

References

Houry DE, Salhi BA. Acute complications of pregnancy. In: Marx JA, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier;2009:chap 176.

Lobo RA. Ectopic pregnancy: Etiology, pathology, diagnosis, management, fertility prognosis. In: Katz VL, Lentz GM, Lobo RA, Gershenson DM, eds. Comprehensive Gynecology. 5th ed. Philadelphia, Pa: Mosby Elsevier;2007:chap 17.

Barnhart KT. Ectopic pregnancy. N Engl J Med. 2009;361:379-387.

Update Date: 2/21/2012

Reviewed by: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington School of Medicine; and 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. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.