What is an ectopic pregnancy?

An ectopic pregnancy is a pregnancy that has implanted in the wrong place. The fertilized egg gets stuck in the fallopian tube instead of traveling through the tube and implanting in the uterus. Once the fertilized egg gets stuck, it implants in the fallopian tube and begins to grow there. This is a potentially dangerous situation. That’s because there is not enough room in the tube for the pregnancy to grow. Within a few weeks, the pregnancy tissue will grow so much that the tube will rupture (burst), causing severe, possibly life threatening internal bleeding. It is very important to diagnose and treat an ectopic pregnancy before it ruptures.

There are three classic signs of an ectopic pregnancy: one-sided lower abdominal pain, vaginal bleeding and a positive pregnancy test. The pain is caused by stretching of the fallopian tube; that’s why the pain is usually on one side only. Most ectopic pregnancies do not grow normally (like pregnancies that are destined to miscarry) and that leads to the vaginal bleeding. Not everyone has the classic signs. Any time you have one-sided lower abdominal pain in the first trimester, it raises the possibility of ectopic pregnancy.

An ectopic pregnancy should also be suspected anytime the levels of pregnancy hormone (HCG) in the blood do not rise appropriately. In a normal pregnancy, the level of HCG will double approximately every 48 hours. In a miscarriage, the HCG level will rise more slowly than expected and begin to gradually fall. In an ectopic pregnancy, the level can be very erratic, rising and falling and rising again.

Ultrasound can sometimes be helpful in diagnosing an ectopic pregnancy. If the baby is seen inside the uterus, it is a normal pregnancy, and ectopic pregnancy does not need to be considered. On the other hand, and empty uterus, along with a mass (growth) near the ovary can be a sign of ectopic pregnancy. However, the ectopic pregnancy may not be visible on the ultrasound. It can be large enough to rupture the tube before it is large enough to be seen on ultrasound.

Since an ectopic pregnancy is a potentially life threatening condition, it must be treated. If the fallopian tube is already bleeding, surgery is the only treatment. The pregnancy tissue can be removed from the fallopian tube through the laparoscope, or, if necessary, the fallopian tube itself can be removed through the laparoscope, inserted in a small incision near the belly button. In the case of severe bleeding, emergency surgery can be performed quickly through a regular abdominal incision.

If there is no sign of bleeding, the ectopic pregnancy can be treated with an injection of methotrexate. Methotrexate is a form of chemotherapy and it will kill the pregnancy tissue. The body will then reabsorb the tissue. A woman who has had methotrexate needs to have her blood HCG levels checked every few days until they return to pre-pregnancy levels. Occasionally, one shot of methotrexate will not be enough, and a second shot will be needed.

The most common, known cause of ectopic pregnancy is a previous pelvic infection that has scarred the fallopian tubes. However, many cases of ectopic pregnancy have no obvious cause. A woman who has had an ectopic pregnancy has an increased risk (approximately 10%) of having another ectopic pregnancy in the future, so she should be monitored carefully at the beginning of any future pregnancies.