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Ectopic pregnancy
Definition:
Ectopic pregnancy occurs when a fertilized egg implants in tissue outside of the uterus, and the placenta and fetus begin to develop there. The most common site is within a fallopian tube. However, ectopic pregnancies can rarely occur in the ovary, the abdomen, and in the lower portion of the uterus (the cervix). Alternative Names:
Tubal pregnancy; Cervical pregnancy; Abdominal pregnancy Text Continues Below
Causes, incidence, and risk factors:
Ectopic pregnancies are usually caused by conditions that obstruct or slow the passage of a fertilized ovum (egg) through the fallopian tube to the uterus. This may be caused by a physical blockage in the tube. Ectopic pregnancy may also be caused by failure of the zygote (the cell formed after the egg is fertilized) to move down the tube and into the uterus.
Most cases are a result of scarring caused by previous tubal infection or tubal surgery. Up to 50% of women with ectopic pregnancies have a medical history of salpingitis or PID (pelvic inflammatory disease). Some ectopic pregnancies can be traced to congenital tubal abnormalities, endometriosis, tubal scarring and kinking caused by a ruptured appendix, or scarring caused by previous pelvic surgery and prior ectopic pregnancies. In a few cases, the cause is unknown.
On occasion, a woman will become pregnant after elective tubal sterilization. The risk of an ectopic pregnancy occurring in this situation may reach 60%. Women who have had surgery to reverse previous tubal sterilization in order to become pregnant also have an increased risk of ectopic pregnancy when reversal is successful.
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