Horseshoes and Hand Grenades

Pop Quiz: How long does it take to have a baby?

The conventional answer is, of course, 9 months. It's what we've been taught for pretty much as long as we've been able to comprehend time. Our parents taught us this, our grade school and high school health classes taught us this, and even project management training teaches us this ("nine women can't have a baby in a month...").

The Catch: It's not actually true.

Scientifically, human gestation is 38 weeks - which in truth is actually about a week shorter than 9 full months, if you do the math. This in and of itself is noteworthy. But the really crazy part is that according to your doctor, you give birth at the end of your 40th week of pregnancy. That's two weeks longer than the standard gestation period!

So what gives? It all goes back to the inexact science of pregnancial estimation. (And yes, I believe I just invented a new adjective - pregnancial, adj, of or pertaining to a pregnancy - rhymes with financial. Try it with your friends.)

Here's how it breaks down, for the uninitiated...

Apparently your pregnancial advisor (i.e. doctor) can't determine the precise date of conception. So what he does is go back to the date of the last menstrual period, and starts counting 40 weeks from there. Since most women get pregnant squarely between their periods, the difference between the 38-week legit gestational timeframe and the 40 weeks after their last period roughly matches up in the end.

Two things that bother me about all of this:

1) Really, your doctor can't figure out when you conceived? We've been giving birth since the evolution of the species, and we still can't figure out when little spermy and eggy got together? Does it seem weird to anyone else that science can tell me how old the universe is, but it can't tell me how old my kid is?

2) They can't precisely nail the conception date, so they don't even bother to try? "Aw, screw it, this conception sh*t is too hard. Let's just add a couple weeks and count from the last mentrual period." Sheesh - let's hope they are a bit more detail-oriented when they are actually delivering the baby.

The numbers, for those of you who are mathematically inclined:

52 weeks per year / 12 months per year = 4.333 weeks per month

Therefore:

Actual gestation from conception =

38 weeks / 4.333 weeks per month = 8.77 months

Doctor's estimate from last menstrual period =

40 weeks / 4.333 weeks per month = 9.23 months

Now, it's entirely possible that my ignorance of all things pregnancial will become a running theme of this blog, but this one just kills me. When one of my college buddies broke this news to us a couple years ago, it was like someone told us the sky was purple.

So yeah, nine months? Close enough...