An ectopic pregnancy is a pregnancy that occurs outside the uterus. Normally, fertilization takes place in the widest section of the fallopian tube. The fertilized egg then travels toward the uterus where it is to be implanted. Ectopic pregnancy happens when the egg gets stuck on its way and starts to develop inside the tube. This is known as tubal pregnancy. Implantation may also occur in the cervix, ovaries and abdominal cavity but tubal pregnancy is by far the most common. With extremely rare exceptions, the fetus cannot survive outside the uterus. Without treatment, the growing tissue may rupture, resulting in destruction of the surrounding maternal structures and a massive blood loss that could be life-threatening.
An ectopic pregnancy may have no signs, or may feel like a normal pregnancy at first, with positive pregnancy test result for hCG. First clinical symptoms usually appear after 4 weeks from the last normal menstrual period and may include abdominal pain, vag. bleeding, or both. There may also be shoulder pain. If the fallopian tube ruptures, heavy bleeding, fainting and shock can be expected. This is a medical emergency and requires immediate attention.
Tubal pregnancy occurs because of problems in transportation of the fertilized egg through the tube. Fallopian tubes are lined with hair-like structures called cilia that help to move the egg through. It is believed that a reduction in number of cilia may slow down the transport and lead to tubal pregnancies. Cilia degeneration can happen as a result of tubal tissue scarring or as an effect of certain chemicals or drugs. Risks factors include:
-Inflammation of fallopian tubes – salpingitis; or infection of pelvic organs - pelvic inflammatory disease. These infections are commonly caused by gonorrhea or chlamydia.
-Use of an intrauterine device as a contraceptive method
-Tubal or intrauterine surgeries such as tubal ligation, tubal reversal and dilation & curettage
-Previous ectopic pregnancy
-Abnormal fallopian tubes due to birth defects
-Exposure to certain fertility drugs
-Daughters of mothers who have taken the synthetic estrogen diethylstilbestrol during pregnancy
Diagnosis is often based on blood tests for hCG and a transvaginal ultrasound.
If the ectopic pregnancy is detected early, methotrexate may be injected to dissolve the pregnancy tissue. In other cases, a keyhole surgery may be performed. If the fallopian tube has ruptured, an emergency open surgery is required. The ruptured tube is usually removed. After treatment the hCG levels are monitored to ensure that the entire ectopic tissue has been taken out. An hCG level that remains high would require further treatment.