The Kollel mentioned the Halachah that a fetus delivered after 8 months, as opposed to 7 or 9, is considered to be as dead, if it can be discerned with certainty that it is not completely formed. If not, it is only Safek dead, and must me treated like a live child.
All modern day poskim from Chazon Ish owards (except for Minchat Yitzchak) pasken that we do not differentiate between a 7 month and 8 month old fetus and in both cases do whatever is necessary even if the baby is not completed formed.
E. Turkel, Raanana, Israel
The Chazon Ish in Yoreh Deah155 #4 writes that circumstances have changed and we are Mechalel Shabbos to save an infant born even in the 7th or 8th month if he has hair and fingernails. However he does not seem to permit Chilul Shabbos if the infant is definitely born in the 8th month and does not have hair and nails.
The Minchas Yitzchak in Chelek 4 Siman 123 #21 discusses the ramifications of modern medicine and the use of incubators for premature babies. In conclusion he writes that it is difficult to rule leniently against the Shulchan Aruch in the case of an infant born definitely in the 8th month and without hair and fingernails.
He finds room to be lenient by adding a number of reasons to be lenient in general:
1) The Meiri, who brings an opinion that nowadays we are not expert in what is considered a completed fetus or not.
2) Medical opinion that most premature infants have nails and hair.
3) The opinions that if there is any doubt that the infant might not be born in the 8th month then we are lenient.
Shemiras Shabbos ke'Hilchasah (36:24) quotes Rav Sh. Z. Auerbach who was lenient and permitted Chilul Shabbos even for an infant born in the 8th month where there is no incubator, because we assume that it is really a 7 month pregnancy which was delayed.
Thank you for bringing this issue to our attention