There's actually NO condition that demands the death of the foetus to cure the woman.
WIth that said, there are conditions that are worsened by the demands of pregnancy which could possibly lead to death of the woman if she were to remain pregnant or the pregnancy was life threatening. However, the pregnancy can be ended with the a live child via. early birth. I hear a lot of cases where people say "Oh, a, b and c will happen if we don't abort" when really, most of these cases where a pregnancy is adversing affecting the woman, they can simply be resolved by bed rest and good medical intervention, until such time as the child is old enough to survive outside the womb.
Subsquently, there are plenty of cases of women dying from various conditions that were not picked up sooner or not properly treated. LIkewise, there are conditions that pop up in pregnancy that kill so quickly as to never really have been picked up at all.
There was a woman in my home town who died a few days after she gave birth due to a complication late in pregnancy which caused a prem labour. Baby survived. Had this condition been predicted earlier, abortion could have been an option, or early labour could have been one. One results in a dead child, one doesn't. Therefore, only one is moral.
There are no guarentees in life, and certainly not with a pregnancy, either people accept that and move on, or they kill a child to try and save themselves, and abortion doesn't always save mummy. I mean, really, any research into late term abortions woudl find that most take place over the period of several days to dilate the cervix to a size that will allow the child ot be removed piecemeal or intact. Can't tell me that late term abortions are required to save a mother's life when she's holed up in a hotel waiting for her cervix to ripen.
As for prevention of pregnancy due to whatever condition that's also rather faulty, no one knows what's going to happen. I had a half brother with autism/epiliepsy and serious allergies, there are quite a few dyslexics in my biological family, including myself, along with other problems, dyslexia, autism and asperges are closely related, there's a good chance I could have a child with autism. Does that mean I should use contraception or abortion to prevent these children being born? Of course not!
Doctors are not always right. I've met my fair share. Trust in God.
If I found myself in a situation where a pregnancy endangered my life, I'd do teh research thoroughly of the condition, take to bed rest, even if that meant hospital, demand pro-life doctors care for me, and try to make it to viability. If I died, then so be it, but i'd rather go to God with a conscience clear of the sin of killing my own child, then live another 60 years knowing I"m a murderer, and then having to explain that to God. In my view, if I'm pregnant, my doctor/lead maternity carer has TWO patients.
As I mentioned above, a woman in my home town passed due to a condition that cropped up. I don't know them personally personally - they're good friends of friends and I've met them a few times. I don't know what their opinion on abortion was, and I don't know if that would have saved the mother, no one does.
I do know of a case where a woman was told she needed an abortion or she'd die, her husband talked her into the abortion, she didn't really want one, but because she had two other children and an elderly father at her house she relented.
The woman died from complications from the abortion. I later heard that the condition wasn't as serious as they thought, the complications that killed her stemmed from a reaction to teh drugs given during the procedure.
Basically, she and baby could have lived.*