Viability Day is the first day that the NICU will do everything in their power to save a baby if, God forbid, something should happen that would require an early delivery.
Even one day before this, most insurance companies won't agree to pay for any type of treatment—and since the odds aren't in the baby's favor before week 24 anyway (this is when their lungs are developed enough to function with assistance), most doctors won't do anything to help.
This chart shows a baby's chance of survival, based on gestational age:
According to the due date my OB gave me*, I'm exactly 24 weeks pregnant today. If my baby boy had to make an early appearance for some reason, my doctor would pull out all the stops to save him. I can't find the words to express how happy this makes me, or what a relief it is—so I'll just say that today's really awesome.
Happy Viability Day, Little Man! Now, don't go getting any crazy ideas—you keep right on cooking until April 2nd.
There are 2 ways to calculate estimated due dates. I first calculated mine based on my ovulation date, which should be the most accurate way. My weekly fruit check-ins correspond with this date—April 7th. My OB goes by the date of the last menstrual period. Since Guido's size has always corresponded better with her date—April 2nd—she kept it.