It Was My Understanding That There Wouldn't Be Any Math

Week 9
October 13, 2008
Mom

You would think figuring out how far along I am would be pretty easy. You'd be wrong.

Calculating the due date is a pretty simple procedure. There's a formula -- I don't know what it is but I'm not an OB -- plug in the dates and viola! a due date. Now there are some different methods, but no matter what is used (with the exception of a dating sonogram) they all come up with May 12 as the due date.

Now with this due date in hand, (ostensibly the hard part) I should be able to come up with a countdown of some sort. Call it an advent calendar for my pregnancy if you will (ooh, will there be chocolate?).

However, when I plug my due date into various pregnancy calculators, web sites and books I get a different result every time. How many days from today until May 12? Seems like it should be pretty basic. (I however, majored in liberal arts in college so maybe I'm asking too much of the numbers people.)

I'll give you some examples using today's date, October 13, 2008:

• What to Expect says I'm 10 weeks but does not provide a days countdown. (Although the way they work, I'll start getting "Week 11" e-mails on Wednesday, so for them I'm 10 weeks, 5 days.)
  
• SheKnows says I'm 9 weeks, (67 days into the pregnancy total) and there are 213 days to go
• The cute little countdown on the side says I'm 9 weeks, 6 days and there are 214 days to go.
• The cool countdown on the bottom of the page says I'm 9 weeks, 6 days and there are 211 days to go.
• My book, The Pregnancy Journal, says I'm 8 weeks, 5 days (55 days) and there are 211 days to go.
• Going back to my sonogram, I'm 10 weeks, 1 day.
• My ob/gyn's countdown says I'm 9 weeks, 6 days.
  

I'm not even going to attempt to figure out how many months along I am. I think that involves the Chinese calendar and a sundial.

Now I know there are different ways to count. The doctor counts from the first day of my last menstrual cycle. Others go back 38 weeks (266 days) from the due date, still others go back 40 weeks (280 days).

My head hurts. Why can't there be some uniform method? Is that too much to ask? Us pregnant ladies have enough going on in our heads, why do I have to break out my graphing calculator and rudimentary knowledge of calculus to figure out how far along I am?

If anyone cares to explain this to me in a way a 4-year-old can understand, I'll be at home counting on my fingers. For now, I'll go with what the ob says.