Imaging studies of Ectopic pregnancy
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Ultrasonography is most useful in excluding a tubal pregnancy by demonstrating an intrauterine gestational sac or fetus. With a quantitative hCG less than 1,500 mIU/mL, this may not be possible, and stable patients should be followed with serial hCG titers. However, an hCG greater than 2,500 mIU/mL and absence of a gestational sac in the uterus indicate either a nonviable intrauterine or an ectopic pregnancy. Ultrasound findings consistent with ectopic pregnancy include a uterus without a well-formed gestational sac—although a pseudosac (intrauterine fluid collection) may be present—free intraperitoneal fluid, and sometimes an adnexal mass representing the tubal pregnancy.
Diagnostic studies of Ectopic pregnancy
- Culdocentesis is useful for detecting hemoperitoneum, although it is used infrequently because sonographic evaluation for free intraperitoneal fluid often is sufficient. A culdocentesis is performed by passing a needle aseptically into the posterior vaginal fornix. Aspiration of clear yellow fluid is normal. If no fluid is obtained, the test is nondiagnostic. Aspiration of clotting blood is likely from an intravascular source and nondiagnostic, whereas nonclotting blood with an Hct above 15% is consistent with hemoperitoneum.
- D & C can be performed to differentiate between ectopic pregnancy and incomplete abortion after excluding a normal early intrauterine pregnancy. Curettage products that float in saline are suggestive of chorionic villi. If villi are not identified, laparoscopy to exclude ectopic pregnancy is indicated.