Any pregnancy located outside of the uterine cavity is defined as an ectopic pregnancy (EP). The vast majority (99 percent) of EP's occur in the fallopian tube ("tube"). More than 100,000 cases occur annually in the United States¹. The incidence of EP continues to increase yearly due to the occurrence of sexually transmitted diseases, prior salpingitis (tubal infections), IUD use, pelvic adhesions and other causes. The death rate from EP is about 0.3 percent². The most sensitive initial indicator of an early pregnancy is a blood test to measure the hormone HCG. Early indicators of a potential EP are a slower-than-expected rise in HCG levels early in pregnancy³ and a low serum progesterone level. Bleeding and/or cramping may be another sign of a possible EP, but these can also occur with an early miscarriage or even in normal pregnancies.

A physician should consider every early pregnancy as a possible EP until proven otherwise. In most cases, the presence of an early intrauterine pregnancy verified by ultrasound will exclude the presence of EP. The exception to this rule is in the case of assisted reproductive technology (ART), such as in vitro fertilization (IVF), or ovulation-induction with injectable FSH. In these ART treatments, the presence of both an intrauterine pregnancy and EP (heterotopic pregnancy) occur more frequently. With good ultrasound equipment and an experienced ultrasonographer, a normal intrauterine pregnancy should be visible by the time a woman is 6 weeks from her last menstrual period (3 1⁄2 to 4 weeks from conception date).

References

1. Goldner TE et al, Surveillance for Ectopic Pregnancy: United States, 1970-1989. MMWR 1993; 42:73-85.
2. Lehner et al, Arch Gynecol Obstet 2000 Feb; 263(3): 87-92.
3. Kadar N, et al, Obstet Gynecol 1981; 58(2): 162-166.