How is ectopic pregnancy diagnosed?
The first step in the diagnosis is an interview and examination by the doctor. The usual second step is to obtain a qualitative (positive or negative for pregnancy) or quantitative (measures hormone levels) pregnancy test. Occasionally, the doctor may feel a tender mass during the pelvic examination. If an ectopic pregnancy is suspected, the combination of blood hormone pregnancy tests and pelvic ultrasound can usually help to establish the diagnosis. Transvaginal ultrasound is the most useful test to visualize an ectopic pregnancy. In this test, an ultrasound probe is inserted into the vagina, and pelvic images are visible on a monitor. Transvaginal ultrasound can reveal the gestational sac in either a normal (intrauterine) pregnancy or an ectopic pregnancy, but often the findings are not conclusive. Rather than a gestational sac containing a visible embryo, the examination may simply reveal a mass in the area of the Fallopian tubes or elsewhere that is suggestive of, but not conclusive for, an ectopic pregnancy. The ultrasound can also demonstrate the absence of pregnancy within the uterus.
Pregnancy tests are designed to detect specific hormones; the beta subunit of human chorionic gonadotrophin (beta HCG) blood levels are also used in the diagnosis of ectopic pregnancy. Beta HCG levels normally rise during pregnancy. An abnormal pattern in the rise of this hormone can be a clue to the presence of an ectopic pregnancy. In rare cases, laparoscopy may be needed to ultimately confirm a diagnosis of ectopic pregnancy. During laparoscopy, viewing instruments are inserted through small incisions in the abdominal wall to visualize the structures in the abdomen and pelvis, thereby revealing the site of the ectopic pregnancy.