In the past, ectopic pregnancies were often not diagnosed until symptoms (e.g., pelvic pain, dysfunctional uterine bleeding) developed several weeks into the pregnancy. Due to advances in medical technology, ectopic pregnancies are now discovered much earlier. In many cases, tests can discover an ectopic pregnancy in the first eight weeks of pregnancy, usually before the organ ruptures.

When common signs and symptoms of ectopic pregnancy are present, a woman may first be given a pregnancy test. When the test comes back positive, or the woman already knows she is pregnant, a number of additional tests may be ordered to diagnose ectopic pregnancy including:

• Human chorionic gonadotropin (hCG) measurement. In a normal pregnancy, levels of hCG (a hormone produced by the placenta) in the blood approximately double every 48 hours for the first 10 weeks of pregnancy. When this increase fails to occur at an appropriate rate it may indicate ectopic pregnancy or miscarriage.
  
  
• Progesterone measurements. During the early stages of pregnancy, the levels of the hormone progesterone in the blood rise. According to the National Institutes of Health (NIH) a serum progesterone level of 25 nanograms per milliliter (ng/mL) or more is associated with a normal pregnancy 98 percent of the time. Low levels of the hormone (less than 5 ng/mL) often indicate ectopic pregnancy or an impending miscarriage.
  
  
• Pelvic examination. During this exam, an obstetrician-gynecologist (ObGyn) examines the pelvic organs for any masses. The exam may also reveal a pregnancy in the uterus or tenderness in the uterine adnexal (fallopian tube or ovary region).
  
  
• Ultrasound examinations. During the early stages of pregnancy, ultrasound can be used to determine whether a pregnancy is located inside the uterus. Ultrasound scans can also reveal fluid or blood in the abdominal cavity, a possible sign of bleeding caused by an ectopic pregnancy. 

In some cases, results from an ultrasound, combined with hCG measurements and/or progesterone measurements, are all that is required for a diagnosis. In other cases, more invasive tests are needed, including:

• Laparoscopy. During this procedure, small incisions are made above the pubic area. Then, a thin lighted tube (laparoscope) is inserted into the abdominal cavity through the incisions. The instrument allows the physician to view internal organs and insert other instruments as needed.
  
  
• Dilation and curettage (D&C). During this procedure, the physician gently scrapes out the lining of the uterus. The tissue sample is then examined for the presence of pregnancy tissue. When pregnancy tissue is not detected in the sample, it may indicate an ectopic pregnancy.  

In addition, a less common test known as a culdocentesis may be used to determine if blood is present in the abdomen. During this procedure, a needle is inserted into the space at the top of the vagina, behind the uterus and in front of the rectum. The test is used to detect fluid or blood in the area that may have resulted from a ruptured ectopic pregnancy.

It may be difficult to detect an ectopic pregnancy that is less than six weeks along. When physicians are unable to diagnose or rule out the condition, they may require their patients to have their hCG levels tested every two days. When these levels do not rise as quickly as they should, the physicians will continue to carefully monitor the patients until the six week mark. At that time an ultrasound can be used to reveal more information.