Preterm birth
James Elgin Gill (born on 20 May 1987 in Ottawa, Ontario, Canada) was the earliest premature baby in the world, until that record was broken in 2014. He was 128 days premature (21 weeks and 5 days' gestation) and weighed . He survived.
Korach (parsha)
Rabban Simeon ben Gamaliel taught that any baby who lives 30 days is not a nonviable, premature birth ("nefel"), because says, "And those that are to be redeemed of them "from a month old" shall you redeem," and as the baby must be redeemed, it follows that the baby is viable.