This is what I know, Linda: Gestation is 10 moons - 280 days, or 266 days from conception (supposedly, assuming your follicular phase is 14 days long). Most doctors I have met go by your LMP, which really confuses them when it comes to me, because my follicular phases were really extended. So we go by my conception date, since we know that exactly.
Including my follicular phase, which they artificially shortened to make it fit into their formula, I'm at 20 weeks out of 40. Gestationally I guess it's 18 weeks the baby has been in there.
Why they do this, I have absolutely no idea. But I can ask my midwife for sure!
The Wise Woman Herbal says that the childbearing year is the 3 months prior to conception plus they 9 months of carrying.
This quote off of the page you linked makes me shudder:
|What I was taught was to add 2 days for everyday over the 28 day cycle. For example, if a woman has a period every 30 days, you would add 4 days to the due date figured on the 28 day numbers. Does that make sense? I have found it to work pretty well. It works well the other direction too. For women that have shorter cycles.. Just subtract 2 days for every day under 28 days.
My cycles were always 35-40 days. GULP!