Is removal of am embryo that is growing in the fallopian tubes considered to be an abortion, and therefore a sin? It is a well-known fact that Catholics are opponents of abortion, as well as any kind of artificial birth control. So, what is the Vatican's opinion of tubal pregnancies and their possible treatment? Well, an official Catholic website declares:
A mother facing a tubal pregnancy risks imminent rupture of the fallopian tube. While the doctor would opt for the least risk and expense to the mother, all the options presented to her involve terminating the pregnancy. The mother, however, must respect both her life and that of her child. Most reputable moral theologians accept full or partial salpingectomy (removal of the fallopian tube), as a morally acceptable medical intervention in the case of a tubal pregnancy.
Catholic discussion forums that I follow always have topics on this subject on the go, or so it seems. Such debates have made it clear to me that most Catholics agree with the approach mentioned in the above quote. Merely removing the embryo from the fallopian tube as soon as ectopic pregnancy was diagnosed (and therefore before the possible rupture of the tube in many cases), is seen as only removing the growing life and therefore it is abortion. Removing the entire tube, which happens to have an embryo in it, is not seen as an abortion but as a medical procedure that sadly costs a life.
The reason behind this stance is that removing the embryo is not the entire point of procedure. The primary goal is saving the mother from tubal rupture, and possible hemorrhage and death. This seems a bit arbitrary to me, and the consequence of removing the full tube, which isn't always necessary, obviously causes problems for future pregnancies.