Bad Bad news folks, I only have ‘words and names’ but no ‘exact sources’
However every word is mamash, Doleh Umashkeh from Poskim and Beki’im (as I said earlier, these include Harav Zev Leff Shlit’a and Rabbi Dr Yitzchok Brietowitz Shlit”a)
Reb Moshe and others hold it is like Retzicha.
It can only be ‘like’ Retzicha for many reasons. Hasra’as Safek that it’s a Tereifah, or Mechusar Shiur Chai.
Tosfos in Niddah holds it is only Issur Miderabanan to abort. (some ask on Tosafos, that if you could be Mechalel Shabbos to save an Ubar, how can it only be Asur Miderabanan to kill?)
Chavos Yair, says it is only issur of Hashchasas Zerah.
Some say it is a Chavalah, causing a wound, either to Mother or Baby
Possible Heterim would be as follows.
1)Tzitz Eliezer says that the Issur of abortion only applies after 7th month. It has been mentioned here that he was a Daas Yachid. However many Poskim did rely on this Shittah in very exceptional cases.
2)Tosafos that holds abortion is only Bittul Piryah Verivyah, and combining with Chinuch that no Mitzvah Peru Urvu by a Mamzer, so in case of rape (of married woman) or incest, you could abort.
3)Reb Yackov Emden holds that you could abort a Mamzer/es, because if a woman is Mezaneh, we would kill her if she even if she is pregnant, and Beis Din do not have to wait until the baby is born, so you could abort in case of voluntary zenus.
4)Chavos Yair that it is Hashchasas Zerah, that is only Assur Shelo Letzorech, so if we can find a good reason to abort, then it is not “Levatalah”.
Most cases where these Shailos come up, the Poskim need good reasons to abort. Morning sickness is not a good enough excuse, sorry 🙁
Situations where they might allow maybe, in a case of a teenager being raped (unlikely scenario because she is not likely to get pregnant), or abuse from family member.
Maybe where the Doctor’s can determine a genetically damaged fetus that will come out completely deformed, brain damage etc.
As always, these cases should be Paskened by a real Rabbi, not us bored rabbles in the Coffee Room.