An ectopic pregnancy occurs when a fertilized egg implants somewhere other than the main cavity of the uterus. Pregnancy begins with a fertilized egg. Normally, the fertilized egg attaches itself to the lining of the uterus. An ectopic pregnancy most often occurs in one of the tubes that carry eggs from the ovaries to the uterus (fallopian tubes). This type of ectopic pregnancy is known as a tubal pregnancy. In some cases, however, an ectopic pregnancy occurs in the abdominal cavity, ovary or neck of the uterus (cervix). An ectopic pregnancy can't proceed normally. The fertilized egg can't survive, and the growing tissue might destroy various maternal structures. Left untreated, life-threatening blood loss is possible. Early treatment of an ectopic pregnancy can help preserve the chance for future healthy pregnancies. Up to 10% of women with ectopic pregnancy have no symptoms, and one-third have no medical signs. In many cases the symptoms have low specificity, and can be similar to those of other genitourinary and gastrointestinal disorders, such as appendicitis, salpingitis, rupture of a corpus luteum cyst, miscarriage, ovarian torsion or urinary tract infection. Clinical presentation of ectopic pregnancy occurs at a mean of 7.2 weeks after the last normal menstrual period, with a range of 4 to 8 weeks. Later presentations are more common in communities deprived of modern diagnostic ability.
Signs and symptoms of ectopic pregnancy include vaginal bleeding (in varying amounts), abdominal pain, pelvic pain, a tender cervix, an adnexal mass, or adnexal tenderness. In the absence of ultrasound or hCG assessment, heavy vaginal bleeding may lead to a misdiagnosis of miscarriage. Nausea, vomiting and diarrhea are more rare symptoms of ectopic pregnancy.
The rate of ectopic pregnancy is about 1 and 2% of that of live births in developed countries, though it is as high as 4% in pregnancies involving assisted reproductive technology. Between 93 and 97% of ectopic pregnancies are located in a Fallopian tube. Of these, in turn, 13% are located in the isthmus, 75% are located in the ampulla, and 12% in the fimbriae. Ectopic pregnancy is responsible for 6% of maternal deaths during the first trimester of pregnancy making it the leading cause of maternal death during this stage of pregnancy.
Between 5% and 42% of women seen for ultrasound assessment with a positive pregnancy test have a pregnancy of unknown location (PUL), that is a positive pregnancy test but no pregnancy visualized at transvaginal ultrasonography. Between 6 and 20% of PUL are subsequently diagnosed with actual ectopic pregnancy.