Ectopic pregnancy test strips indicate that the gestational sac is implanted outside the uterine cavity, with the most common type being a tubal pregnancy. The bleeding caused by a tubal pregnancy includes two types: vaginal bleeding and intra-abdominal bleeding.

Firstly, the vaginal bleeding caused by an ectopic pregnancy mainly occurs because the gestational sac lacks a normal developmental environment, with relatively low levels of estrogen and progesterone. This leads to insufficient endometrial proliferation, resulting in regressive bleeding. Typically, vaginal bleeding appears around the fifth week of an ectopic pregnancy, but the amount of bleeding is generally small.

Secondly, if the gestational sac in an ectopic pregnancy is relatively large, it can cause the local rupture of the fallopian tube, leading to intra-abdominal bleeding. This usually occurs around the seventh to eighth week of pregnancy. If the gestational sac is too small, even if there is mild abdominal pain, it will not cause intra-abdominal bleeding.