An ectopic pregnancy is classified according to where exactly the fertilized egg implants. Some examples of the different types of ectopic pregnancy are described below.

Tubal pregnancy

A tubal pregnancy occurs when the egg has implanted in the fallopian tube. This is the most common type of ectopic pregnancy and the majority of ectopic pregnancies are tubal pregnancies. The type of tubal pregnancy can be further classified according to where inside the fallopian tube the pregnancy becomes established.

• A pregnancy grows in the fimbrial end in around five percent of all cases.
• A pregnancy grows in the ampullary section in around 80% of all cases.
• A pregnancy in the isthmus of the fallopian tube is seen in around 12% of all cases. Increased vasculature in this area means hemorrhage is more likely to occur and mortality of the pregnancy is therefore more likely.
• A pregnancy in the cornual and interstitial part of the fallopian tube is seen in around two percent of cases and again is more likely to lead to mortality of the pregnancy due to increased vasculature in this area.

Non-tubal ectopic pregnancy

Nearly two percent of all ectopic pregnancies become established in other areas including the ovary, the cervix or the intra-abdominal region.

Heterotopic pregnancy

In some rare cases, one fertilized egg implants inside the uterus and another implants outside of the structure. The ectopic pregnancy is often discovered before the intrauterine pregnancy, mainly due to the painful nature of ectopic pregnancy. If human chorionic gonadotropin levels continue to rise after the ectopic pregnancy has been removed, the pregnancy inside the womb may still be viable.