But I didn't actually know how many weeks there are in a nine-month pregnancy.
Turns out there's different opinions [still!] about how long an average pregnancy lasts! This is because only 3% are born on the due date.
But even so. I know nothing about statistics, but the number of births in the history of the world should have given some average.
But Nicky Wesson's Labour Pain: A Natural Approach to Easing Delivery mentions three calculations:
- 40 weeks - 10 menstrual cycles - (Naegele's Rule, 19th Century)
- 41 weeks and one day - for white women expecting their first child (Mittendorf, 1991). Black women, he says, and most women under 19 or over 34, are likely to give birth earlier than this. Can this be true?
- 42 weeks (Montgomery's Rule, 1837)
If my doctor says the due date is 19th Dec, but AW got a different date when calculating on the internet, I'd like to know who's right and which system they're using.
The online Medical College of Wisconsin's calculator also comes up with 19th Dec as our due date. It also helpfully points out
- the end of the first trimester (12 weeks) is Wednesday, March 28, 2007
- the end of the second trimester (27 weeks) Wednesday, June 6, 2007
Aha! The Babyzone online calculator similarly comes up with 19th Dec, and confirms that this calculation is a 40 week one. That's the Naegele Rule, 19th Century. Nicky Wesson is very disparaging about this one.
And if Mittendorf (1991) is correct, then our baby's going to be born on or after Christmas. Although AW is over 34.
It's going to be a bizarre Christmas.
