- Last Updated: November 30, 2016
An ectopic pregnancy occurs when the fertilized egg attaches somewhere other than the lining of the uterus. There are a few different subtypes of ectopic pregnancy (abdominal, cervical, ovarian) but by far the most common is the tubal pregnancy (98% of all ectopic pregnancies).
A tubal pregnancy is characterized by an egg that attaches in one of the fallopian tubes which normally function to move the egg from the ovary to the uterus. Once the egg implants in the tube it is no longer viable and pregnancy cannot proceed. About 50% of tubal pregnancies will result in natural abortion. However, the implantation of the egg and its further growth can cause serious bleeding for the mother.
Ectopic pregnancies can exhibit symptoms similar to regular pregnancies, so an ultrasound examination is performed to confirm that the embryo implanted normally. Abdominal and lower back pain as well as abnormal vaginal bleeding can be signs of an ectopic pregnancy. If the fallopian tube ruptures, symptoms can include shock, lightheadedness and heavy bleeding. This is a potentially life-threatening occurrence for the mother.
The exact cause of ectopic pregnancy is not always known. However, the egg is usually obstructed by inflamed, damaged or abnormally shaped tubes. Hormone imbalances and abnormal fetal development may also play a role. Risk factors for having an ectopic pregnancy include advanced age, previous ectopic pregnancies, endometriosis and accidental pregnancy with an implanted intrauterine device (IUD).
It is estimated that ectopic pregnancy has an incidence as high as 20 in every 1000 pregnancies. Hemorrhage from ectopic pregnancy is the leading cause of maternal mortality during the first trimester and accounts for 10-15% percent of all maternal deaths.
In some cases, ectopic pregnancies will naturally abort and no intervention is needed. Physicians may monitor the levels of the pregnancy hormone human chorionic gonadotropin (HCG) to ensure abortion is progressing.
Pregnancies that are detected early can be treated with medication to arrest development of the embryo, which is then resorbed by the women’s body or eliminated from the body during the next menstrual period. The approach avoids surgery and its associated complications. However, side effects of the medication can include nausea, fatigue, vaginal bleeding and abdominal pain, and several weeks of HCG testing are often needed to determine complete termination of the pregnancy.
Tubal pregnancies that are not discovered early on usually require surgery. The embryo cannot develop normally outside the uterus and therefore the tissue must be removed. Laparoscopic surgery, which requires a small incision in the abdomen, is generally sufficient for removing the embryonic tissue. In more serious cases where there has been tubal rupture and heavy bleeding, emergency surgery is required via a more significant abdominal incision (laparotomy) to remove the damaged fallopian tube. Complications from surgery include scarring and fallopian tube damage that may hinder future pregnancies.
Focused Ultrasound Research
Focused ultrasound treatment for tubal pregnancy has not yet been approved. In a 2011 study, 40 patients diagnosed with ectopic tubal pregnancies (28 non-ruptured, 12 ruptured) participated in a clinical trial in Shaanxi Province, China. The focused ultrasound treatment was successful in reducing serum HCG levels and reducing ectopic tissue volume in 82% (33 of 40) of the patients. All 7 unsuccessful treatments were patients that had suffered ruptured tubal pregnancies and required further surgical intervention. This suggests that focused ultrasound could develop into a non-invasive treatment option for patients with nonruptured ectopic pregnancies. Long-term post-treatment follow up and large sample studies are still needed to reinforce these results.
This material was reviewed in November 2016, and there were no additional clinical trials or publications to add this information.
He GB1, Luo W, Zhou XD, Liu LW, Yu M, Ma XD. A preliminary clinical study on high-intensity focused ultrasound therapy for tubal pregnancy. Scott Med J. 2011 Nov;56(4):214-9.