This was a redfish tournament, where the fish caught were between about 2 and 6 pounds, weights, I noted, pretty similar to those of the premature babies we take care of. The fishermen got credit for their two biggest fish of the day to be weighed. If they already had two and caught a bigger one, they would throw back a smaller one.
Sometimes we wish we could throw a tiny baby back into the uterus to grow some more, but it obviously doesn't work that way with humans. (That doesn't stop people from joking about it, though. If I had a nickel for every time I heard an obstetrician joke about throwing a tiny one back, I'd be able to retire now.) Occasionally someone talks about a need for an artificial placenta, but nothing has really come of it.
And that might be a good thing. We already struggle with the ethics of taking care of 23 and 24 weekers, babies with mortality and disability rates higher than we would like. What if we had an artificial placenta that we could hook 20 weekers up to? What if we could save some, maybe 20 percent, with a 50 to 75 percent major disability rate in survivors, rates worse than those of our current 23 weekers? Would we be offering that care to parents of such babies? What if some babies at even lower gestations survived, but only a small percent? Where would we stop?
Now, at least, we have a barrier at about 22 to 23 weeks below which no babies survive, because the alveoli - the air sacks in the lungs - are just too far away from the blood vessels that go to the lungs, so carbon dioxide and oxygen can't be exchanged. It's sometimes said that our advances in technology outstrip our advances in ethics (although I don't really think that's true), but hey, it could be worse. Maybe it's good we have the barrier of 22 to 23 weeks - although that's hardly any comfort to the parents of a lost 21 weeker.