Typically, they DON’T think that way. Abortion proponents sometimes use that caricature, but the vast majority of pro-lifers do not hold that view.
Basically, pro-lifers believe that we have an obligation to honor the sanctity of life. Ergo, if the mother’s life is not in danger, at major risk, abortion is not justified. If the mother’s life is endangered and the fetus is viable, then a premature delivery is recommended. Conversely, if the mother’s life is in serious jeopardy, and if the unborn has no hope of surviving (e.g. in the case of ectopic pregnancies), then most pro-lifers consider this to be a medically necessary procedure. (Also, Dr. Jack Willke points out that, in any event, such procedures are not abortions in the typical sense of the word.)
Now there may be some situations where the physician can must choose between saving the mother or the child. (I say “may be” because such situations are largely hypothetical, and because the fetus can typically be delivered via C-section if has reached viability.) If such a situation occurs, then the physician must use his best judgment to determine which person to save. In other words, his paramount duty is to uphold the value of human life, rather than to throw it away.
They do an ultrasound. An average woman in an average cycle will release one egg - possibly two and in very rare cases more - without any fertility drugs. On Clomid I released between 5 and 9 eggs estimated during each cycle. On Fertinex I had an 11+ egg cycle (we stopped counting). But the ultrasound is an estimation only (you can’t get a total view of the overies), and there is no guarentee eggs will be actually released, fertilized or implant - the vast majority of released eggs will not result in a pregnancy. I never conceived while on fertility drugs - or to put it more accurately, never became pregnant. My RE suspects I conceived plenty, but my problem was implantation.
To the best of my knowledge, all fertility drugs will produce in the average woman more than three eggs per cycle, assuming it stimulates ovulation in that woman at all.
Multiple births from fertility treatments are not rare, twins being a common outcome, and triplets and maybe quads being a risk you should consider. Quints are rare enough to be a negligible risk. At least this was the case five years ago when I was going through treatment.
Sorry. I was trying to put this from a pro-lifer’s viewpoint, but human lives still might have been a better choice of words. When I wrote this, I was also thinking of the couple that had nonuplets (?). From what I’ve heard, one of the reasons that they carried all of them to term was because they felt it was immoral to choose. This is how it looks to those who see the embryos as human lives: it’s choosing between your offspring, which is a sticky situation all around.