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.