Silly Question - I'm full of them

[AliciaK]

Why, when you do the pregnancy ticker, does it ask first day of last menstal cycle and work out how many weeks pregnant on that??? I know I ovulated on 18 Sept, and believe that is the day we got pregnant, which would only make me 2wks and 2 days pregnant, but the tickers all say 4 wks and 2 days ????
I know it doesn't really matter, but thought I'd ask LOL

[Indadhanu]

Pregnancy is calculated from the first day of your last cycle, not ovulation, which is why a full-term pregnancy is 40 weeks, or about 10 months... cos it includes the first two weeks when the egg/follicle is growing

[MantaRay]

Yep, as Alisia said - your ob or mw will use the same method as well - using your LMP (Last Menstrual Period) date. So congratulations - you are two weeks further along than you thought!

[SammyRo]

I was confused with this too. One book I have talk in how many weeks you are, from your last period. However, the other one talks about weeks from conception, so my head is struggling to get around it all!

[Clueless]

Its definitely from the first day of bleeding of your last period. I have all kinds of crazy cycles and the one before I became pregnant was 51 days long! But the doctor told me they would still calculate my due date from that first day no matter how long my cycle was. The dating ultrasound then becomes the thing they can adjust the dates from if needed.

[sassy123]

yeah when u go to the doc to they ask u for the date of ur last af. her date was exactly wat i worked otu for my ticker. i guess they did it this was because most people dont even know about ovulation let alone when they ovulated. so really the first 2 weeks ur not preg

[hannahfroodoo]

The convention is to count a pregnancy as 40 weeks - so yes, for the first 2 weeks you aren't actually pregnant and you will always get an 'extra' 2 weeks added on to your ticker. They do it this way since - according to the medical profession - most women don't know when they ovulate but can usually remember when they had their last period.
It's kind of nice because you get a 'bonus' - as soon as you find out you are pregnant, you can already say you are 4 weeks along. LOL Some info you read will talk about a 38 week pregnancy which is obviously dating the pregnancy from conception rather than LMP.
A 'normal' cycle of course, is one where you ovulate about CD14. If you know for a fact that you ovulated later than that, tell your Dr when you go for your first appt so they can calculate your EDD more correctly. I make them calculate my EDD based on my O date since I have long (50 days +) cycles and they are quite happy to do it that way.