Ectopic pregnancy (also known as tubal pregnancy) is any pregnancy implanted outside the uterus. It usually occurs in the fallopian tubes, but may occur in the ovary, cervix, abdomen or the site where the fallopian tube and the uterus join.

In a normal pregnancy, a woman’s egg passes through the fallopian tube and becomes fertilized. Now known as an embryo, it continues through the fallopian tube into the uterus. Once in the uterus, the embryo implants in the uterine wall and begins to develop. When the embryo implants in an organ outside of the uterus, such as the fallopian tube, it may cause the organ to rupture. This can lead to severe bleeding and possibly shock, a life-threatening condition caused by lack of blood flow. To prevent rupture of the internal organs, the embryo must be removed. Ectopic pregnancies are not allowed to continue to term due to the risk of death for the mother.

Ectopic pregnancies result from an embryo’s inability to make its way through the fallopian tube to the uterus. Conditions that may block or slow this passage include fallopian tube abnormalities, such as those caused by sexually transmitted diseases (STDs), endometriosis and pelvic inflammatory disease (PID).

Common signs and symptoms of ectopic pregnancy include pain in the pelvis or lower abdomen, as well as common signs of early pregnancy, such as amenorrhea (absence of menstruation) and breast tenderness. Signs and symptoms of a ruptured ectopic pregnancy are often more severe. They can include sharp and sudden pain in the lower abdominal area, fainting with low blood pressure and shock.

The condition is normally diagnosed in the first eight weeks of pregnancy, usually before the organ ruptures. Early diagnosis is achieved through the use of blood tests for hormone levels, ultrasound exams, laparoscopy or dilation and curettage. The condition is treated soon after it is diagnosed in order to prevent complications. Medical treatment for ectopic pregnancy can include the use of medication (e.g., methotrexate) or surgery to remove or destroy the pregnancy tissue. In many cases, the organs can be preserved. However, several types of surgical treatments can lead to infertility because of the possibility of post-operative adhesions. Following treatment, women are also at an increased risk for another ectopic pregnancy.

According to the American Society for Reproductive Medicine (ASRM), ectopic pregnancies account for 1 to 2 percent of all pregnancies in the United States. A woman is more likely to develop the condition as she ages. The risk is also higher for black and Hispanic women, and those who have had three or more pregnancies.

Although ectopic pregnancies occurring in the ovary, cervix and abdomen are not preventable, a woman may reduce her risk of tubal pregnancy by avoiding conditions that may lead to scarring in the fallopian tubes (e.g., having multiple sex partners, failing to use a condom), all of which carry an increased infection risk (e.g., chlamydia).