What is an Ectopic Pregnancy?
By Dr. Kate Dudek
Ectopic literally means ‘out of place’ and an ectopic pregnancy happens when a fertilised egg implants somewhere other than the uterus, normally in the fallopian tube. It is estimated to affect 1-2% of pregnancies and is the most common serious complication of early pregnancy. Unfortunately when a pregnancy is ectopic it cannot be saved and the main aim is to remove it as quickly and safely as possible.
It can be difficult to diagnose a pregnancy as ectopic because often the symptoms are no different from those of a normal pregnancy. There might be some vaginal bleeding, which could easily be mistaken for regular menstrual bleeding, although it usually stops and starts and may be watery in consistency. Persistent pain on one side of your abdomen is another symptom, as is pain in your shoulder tip. This may seem an unusual place to experience pain, but it is thought to be due to internal bleeding and, therefore, should be investigated by a medical professional immediately. Other symptoms include feeling generally unwell and pain or discomfort when going to the toilet. A blood test may show that levels of the hormone human chorionic gonadotropin (hCG), which increase during a normal pregnancy, are rising more slowly than would typically be expected.
If the ectopic pregnancy grows too large, the fallopian tube will rupture. This is a serious event and will require immediate surgery to remove both the pregnancy and the affected fallopian tube. Symptoms of a ruptured tube include a sharp, sudden, intense pain, dizziness, nausea and a pale complexion.
In some cases, the body will dissolve the ectopic pregnancy by itself. This is most likely if the ectopic pregnancy is small, general health is stable, pain is manageable and hCG levels are falling. The period of waiting for an ectopic pregnancy to end naturally is known as expectant management. 50% of women who are suitable candidates for this treatment approach will avoid the need for medication and/or surgery. If symptoms do not improve, or suddenly worsen, an alternative approach will be necessary.
If the situation is not critical and the mother’s life is not at risk, the drug methotrexate might be prescribed to end the ectopic pregnancy. It is given as an intramuscular injection and works as an antifolate. This means it stops the ectopic cells from using folic acid to make DNA and, thus, inhibits their growth. The success rate of this type of treatment is estimated to be approximately 75%, however, some women will need repeat injections. Common side effects include nausea and gastrointestinal problems and women are advised to avoid falling pregnant again for at least three months afterwards to avoid drug-induced damage to the developing foetus.
In some cases of ectopic pregnancy, only surgery will suffice. The most widely used technique is laparoscopy, which is where a camera is inserted through a ‘keyhole’ sized incision and used to locate and identify the ectopic mass. If the fallopian tube has already ruptured and you are bleeding internally a larger incision will be made so that the surgeon can control the situation as quickly as possible. This is called a laparotomy. Whether you undergo a laparoscopy or a laparotomy the main aim is to remove the ectopic cells as efficiently as possible and, in most cases, the entire fallopian tube will also be removed. This is called a salpingectomy. If the other fallopian tube is damaged then doctors will attempt to preserve the fallopian tube containing the ectopic pregnancy by performing a salpingostomy. This is where a small cut is made in the fallopian tube and the ectopic cells removed through the incision. The risk of this technique is that not all of the cells will be removed, so hCG levels will be monitored over the days and weeks that follow to ensure that they start to fall. If necessary, follow-up surgery will be performed to remove the entire fallopian tube. Provided your remaining fallopian tube is healthy, a salpingectomy should not prevent you from falling pregnant again. Following surgery for an ectopic pregnancy, your blood type will be checked and if you are rhesus negative you will be given an anti-D injection to avoid problems with future pregnancies.
What causes an ectopic pregnancy?
It is not well understood why some pregnancies are ectopic, but there are certain factors that increase your risk. The risk for females that have undergone fertility treatment is up to four fold higher than for women who have conceived naturally. Furthermore, if you have already experienced one ectopic pregnancy the chance of your next pregnancy also being ectopic is 10%. Women who have endometriosis are at increased risk, as are those who have a history of pelvic inflammatory disease. Approximately 95-98% of ectopic pregnancies occur in one of the fallopian tubes, however, in rare cases they can also occur in the abdomen, usually at old surgical sites. Women who have previously undergone a C-section are at increased risk of an ectopic pregnancy forming where the scar is. Another risk factor is smoking. Studies suggest that the presence of certain chemicals found in cigarettes cause gene expression changes that disrupt the progress of the fertilised egg through the fallopian tube. One example is the gene PKOKR1, which regulates smooth muscle contraction and could, therefore, feasibly influence embryo transfer through the fallopian tube. It is advisable for all women to stop smoking prior to attempting to conceive.
Previous miscarriage does not increase your risk of experiencing an ectopic pregnancy and there is no evidence that it is an hereditary condition, meaning that even if a close family member has one, your risk is no greater than the general population.
An ectopic pregnancy can be devastating and it is important to not only give your body time to recover, but also allow yourself the opportunity to grieve. Quite apart from the loss of the pregnancy, you may be recovering from surgery and/or coping with the side effects of your medication. If you are struggling to cope, speak to a medical professional.
- “Ectopic Pregnancy.” NHS, www.nhs.uk/conditions/ectopic-pregnancy/. Page last reviewed: 27/11/2018.
- Hackmon, R, et al. “Effect of Methotrexate Treatment of Ectopic Pregnancy on Subsequent Pregnancy.” Canadian Family Physician, vol. 57, no. 1, Jan. 2011, pp. 37–39.
- Shaw, J L, et al. “Evidence of Prokineticin Dysregulation in Fallopian Tube from Women with Ectopic Pregnancy.” Fertility and Sterility, vol. 94, no. 5, Oct. 2010, pp. 1601–1608. doi:10.1016/j.fertnstert.2009.10.061.
- Van Mello, N M, et al. “Methotrexate or Expectant Management in Women with an Ectopic Pregnancy or Pregnancy of Unknown Location and Low Serum HCG Concentrations? A Randomized Comparison.” Human Reproduction, vol. 28, no. 1, Jan. 2013, pp. 60–67., doi:10.1093/humrep/des373.
- “What Is an Ectopic Pregnancy?” The Ectopic Pregnancy Trust, https://ectopic.org.uk/patients/what-is-an-ectopic-pregnancy/.