ECTOPIC PREGNANCY OVERVIEW

Ectopic pregnancy occurs when a developing embryo implants at a site other than the inside wall of the uterus. A brief overview of early pregnancy may be helpful in understanding ectopic pregnancy.

Normal pregnancy — A woman's reproductive system includes the uterus, two ovaries, two fallopian tubes, and the vagina. The fallopian tubes are narrow tubes that link the ovaries and uterus (figure 1).

When an egg and sperm join, they rapidly begin to develop new cells. This group of cells, called the embryo, normally implants on the inner lining of the uterus, called the endometrium. Once implanted, the embryo continues to grow and also forms the placenta, the organ that provides a blood supply for the developing embryo.

Ectopic pregnancy — In an ectopic pregnancy, the developing embryo does not implant on the endometrial wall, but instead attaches to some other surface. For ninety eight percent of pregnancies outside the uterus, that surface is within the fallopian tube. This is also called a tubal pregnancy.

Very rarely, the developing embryo will attach to another site, such as the cervix or an ovary. It can also implant at the site where the fallopian tube and uterus join; this is called an interstitial pregnancy. The embryo can also attach to the abdominal wall.

Rarely, in twin pregnancies, one embryo implants in the uterus and the other implants at an ectopic location. This rare event is called a heterotopic pregnancy and occurs more commonly in women undergoing infertility treatments.

Why is ectopic pregnancy dangerous? — Embryos that do not implant in the uterine wall are generally unable to develop normally. In addition, an ectopic pregnancy can cause rupture of the organ on which they are implanted, typically the fallopian tube.

Rupture can result in severe internal bleeding, shock, and, rarely, death of the woman. Fortunately, the ability to diagnose, monitor, and treat ectopic pregnancy reduces the risk of these life-threatening complications.

ECTOPIC PREGNANCY RISK FACTORS

A number of factors increase the risk of having an ectopic pregnancy.

Strong risk factors

• Abnormalities of the fallopian tubes — If the fallopian tubes are damaged or abnormal as a result of previous infection or surgery, tumors, or, rarely, due to malformations present since birth, there is an increased risk of ectopic pregnancy. Surgery to reconstruct the fallopian tube (to improve a woman's chances of becoming pregnant) can increase the risk of ectopic pregnancy.
• Previous ectopic pregnancy — Women who have had one ectopic pregnancy have an increased risk of having another. The underlying tubal disorder that led to the first ectopic increases the risk for another ectopic pregnancy.
• In-utero diethylstilbestrol (DES) exposure — Women whose mother took DES while pregnant are more likely to have abnormalities of the fallopian tubes and are at increased risk for an ectopic pregnancy.

Moderate risk factors

• Previous genital infections — Pelvic infection with gonorrhea or chlamydia is a major cause of tubal problems and increases the risk of ectopic pregnancy. (See "Patient information: Gonorrhea (Beyond the Basics)" and "Patient information: Chlamydia (Beyond the Basics)".)
• Infertility — The incidence of ectopic pregnancy is higher in women with infertility, mostly due to an increased incidence of tubal abnormalities. Fertility drugs may also increase the risk in this population. (See "Patient information: Evaluation of the infertile couple (Beyond the Basics)".)
• Multiple sexual partners — Having more than one sexual partner is associated with an increased risk of pelvic infection, and therefore an increased risk of ectopic pregnancy.

Other risk factors

• In vitro fertilization (IVF) — IVF, a fertility treatment in which a woman's egg is fertilized outside the body and then placed in her uterus, is associated with an increased risk of both ectopic and heterotopic pregnancy. (See "Patient information: In vitro fertilization (IVF) (Beyond the Basics)".)
• Tubal sterilization — Tubal sterilization (having the "tubes tied" or “clipped”) is a surgical procedure in which the fallopian tubes are cut, clamped, or burned. Rarely, tubal sterilization fails and pregnancy can result. Women who become pregnant after tubal sterilization have a higher risk for ectopic pregnancy. (See "Patient information: Permanent sterilization procedures for women (Beyond the Basics)".)
• Intrauterine contraceptive devices — Women who use an intrauterine contraceptive device (IUD) are less likely to have an ectopic pregnancy than most women, because the IUD is effective at preventing all types of pregnancy. However, if a pregnancy occurs in a woman using an IUD, there is a high risk that it will be an ectopic pregnancy.   (See "Patient information: Long-term methods of birth control (Beyond the Basics)".)

ECTOPIC PREGNANCY SYMPTOMS

Symptoms of ectopic pregnancy, when they occur, appear early in pregnancy, often before the woman realizes she is pregnant. The most common symptoms include:

• Abdominal pain
• A missed menstrual period
• Vaginal bleeding, which may be minimal
• Symptoms of pregnancy (such as breast tenderness, frequent urination, or nausea)

However, over 50 percent of women have no symptoms until the fallopian tube ruptures. Following rupture of the tube, the woman may experience severe pain and some may have vaginal bleeding. Lightheadedness or dizziness may occur first, followed by a drop in blood pressure, fainting, and shock.

Sometimes, the embryo is expelled by the fallopian tube before rupture occurs. This is called a "tubal abortion." Women who have tubal abortion can develop either severe bleeding, requiring surgery, or minimal bleeding that does not require treatment.

Ectopic pregnancies rarely resolve on their own. However, an ectopic pregnancy poses a great risk to the woman and it should be treated as soon as possible after it is diagnosed.

ECTOPIC PREGNANCY DIAGNOSIS

Tests used to diagnose an ectopic pregnancy include a transvaginal ultrasound and a blood test that measures the pregnancy hormone, human chorionic gonadotropin (hCG).

• Ultrasound uses sound waves to visualize structures within the body. In a transvaginal ultrasound, the ultrasound transducer is inserted into the woman's vagina allowing clearer visualization of the uterus and other pelvic organs. It can generally detect intrauterine pregnancies that are 5 to 6 weeks along.
  
  Ultrasound is most useful for identifying pregnancy inside the uterus. A negative pelvic ultrasound (that is, not seeing anything) does not mean that there is no ectopic pregnancy, since approximately 15 to 26 percent of women with an ectopic pregnancy will have a negative ultrasound.
• hCG is a substance secreted by the developing embryo/placenta. The hCG blood level is measured to confirm a pregnancy and can be used to monitor the progress of the pregnancy.

How do I know if I have an ectopic pregnancy? — Ectopic pregnancy is diagnosed if the ultrasound detects a fetal heart beat or an embryo that is outside of the uterus. Since ectopic pregnancies may not be detected by ultrasound, the hCG level is also measured. If the hCG is above a certain level (usually 1500 to 2000 mIU/mL), but no pregnancy is seen with ultrasound, an ectopic pregnancy is suspected.

If the hCG is below 1500 to 2000 mIU/mL and the ultrasound is negative, this may indicate either an ectopic pregnancy or an early intrauterine pregnancy. When this happens, the ultrasound and hCG are repeated every few days until an ectopic pregnancy can be either confirmed or ruled out.

Women with moderate or strong risk factors for ectopic pregnancy, and those who conceived after IVF, are often monitored with ultrasound and blood testing after their first missed period to detect and treat a potential ectopic pregnancy.

ECTOPIC PREGNANCY TREATMENT

An ectopic pregnancy must be treated to stop its growth; observation or "watch and wait" treatment is never recommended because the life of the woman is at risk if treatment is delayed. Treatment is started as soon as a diagnosis of ectopic pregnancy is confirmed, and includes either medication or surgery.

Medical management — Approximately one-third of women with ectopic pregnancies can be treated with a medication called methotrexate, which stops the growth of the embryo. It is given in an intramuscular injection. After the injection, the woman may experience abdominal pain or cramps, which can usually be controlled with acetaminophen (Tylenol®). Nonsteroidal antiinflammatory drugs (eg, ibuprofen/Advil®/Motrin® or naprosyn/Naproxen®/Anaprox®) should be avoided due to the risk of an interaction between NSAIDs and methotrexate.

hCG levels are monitored after treatment until the level has fallen to undetectable. Some women may need additional methotrexate injections.

Methotrexate is most successful in women who have an ectopic pregnancy without symptoms (eg, pain), and whose hCG level and ultrasound results fall within specified limits. When used in appropriate situations, treatment with methotrexate is successful up to 95 percent of the time. If treatment with methotrexate is unsuccessful, tubal rupture can occur. This complication can be avoided with close monitoring and surgical management, if needed.

Surgical management — Surgery is sometimes recommended as treatment for ectopic pregnancy. Indications include:

• Ruptured ectopic pregnancy, surgery often needs to be done immediately, especially if the woman's blood pressure has fallen and she is unstable.
• A woman who is unable or unwilling to return for monitoring after methotrexate therapy.
• A woman who would normally be a candidate for medical treatment, but who could not reach a hospital (due to lack of transportation or distance to an appropriate healthcare facility) in the event of tubal rupture during medical therapy.

How is surgery performed? — Surgery may be performed using a laparoscopic approach or through an abdominal incision. In laparoscopy, instruments are inserted into the abdomen through a few small incisions. These instruments are used to see and remove the ectopic pregnancy and control bleeding. Compared to abdominal surgery, laparoscopic surgery causes less pain and allows for a faster recovery.

In an abdominal procedure, a surgeon opens the abdomen using a single larger incision to directly see and remove the ectopic pregnancy.

Will my fallopian tube be removed? — During surgery, it is sometimes possible to remove the ectopic pregnancy and repair the tube (called salpingostomy).

In other cases, it is necessary to remove the fallopian tube (called salpingectomy). This may be required if there is uncontrolled bleeding, recurrent ectopic pregnancy in the same tube, a severely damaged tube, or a large tubal pregnancy. It may also be performed in women who have completed childbearing.

In a small number of women treated surgically, embryonic tissue may still be present after surgery and cause the hCG level to remain elevated. A dose of methotrexate may be given if this occurs.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient information: Ectopic pregnancy (The Basics)
Patient information: Pregnancy in Rh-negative women (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient information: Gonorrhea (Beyond the Basics)
Patient information: Chlamydia (Beyond the Basics)
Patient information: Evaluation of the infertile couple (Beyond the Basics)
Patient information: In vitro fertilization (IVF) (Beyond the Basics)
Patient information: Permanent sterilization procedures for women (Beyond the Basics)
Patient information: Long-term methods of birth control (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Abdominal pregnancy, cesarean scar pregnancy, and heterotopic pregnancy
Cervical pregnancy
Clinical manifestations, diagnosis, and management of ectopic pregnancy
Expectant management of ectopic pregnancy
Incidence, risk factors, and pathology of ectopic pregnancy
Methotrexate treatment of tubal and interstitial ectopic pregnancy
Surgical treatment of ectopic pregnancy and prognosis for subsequent fertility

The following organizations also provide reliable health information.

• National Library of Medicine

     (www.nlm.nih.gov/medlineplus/healthtopics.html)

• The Nemours Foundation

     (http://kidshealth.org)

• Planned Parenthood Federation of America

    (www.plannedparenthood.org)

• Mayo Clinic

     (www.mayoclinic.com)

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