Quoting HopingforaMiracle:" The only 21 weeker I know that survived is one who was born at 21w6d. Her mom had to lie and tell them ... [snip!] ... My 32 weeker was on the vent. I know of babies earlier that breathe on their own however. But definitely not at 21 weeks"
this is that story about the woman with IVF in Florida, right?
here is the thing tho... it was IVF, so her 21w6d were measured from IMPLANTATION
which means, it's an equivalent of a 23w6d prenancy that's non IVF
it's a famous case, but actually, we would normally describe that as an almost 24 weeker
no one survives at 21 weeks or 22 weeks. i think the very earliest cases begin at 23 weeks, and even those are probably not counted correctly
until you have lungs that are capable to inflating, and being treated with surfactant, there is just no way at all to breathe, so no possibility of survival.
one final note. while technology has improved in the sense that the odds
of a 26 weeker are much better than they were, the actual limit
of viability - the very earliest that a baby can survive outside the womb - hasn't changed in a very long time, at least 20 years