Confusion over dates!

[mrs_bump]

Hi, I was wondering if you ladies could help me? According to my LMP (31/10/11) I am 5 weeks pregnant (as it says on my tickers!) BUT I know there is no physical way I could have conceived before 15th November which would make me 3 weeks. So what am I? 5 or 3 weeks and what will the Drs/midwives use for the rest of my pregnancy? Thank you so much for your help xx

 

[nikki8092]

technically both dates are correct, if you go by LMP it would be 5 weeks, but if you go by ovulation its 3 weeks. Docs go by LMP but obviously you are not pregnant until you ovulate. Thats why when they give you your due date they say 2 weeks either side of 40 weeks xx

 

[misscrazycooki]

you add on the first two weeks as you weren't pregnant then but its to do with the total cycle length x

Why is there a difference between my official week of pregnancy and the length of time my baby has been developing?

You may notice that there is a difference of about 2 weeks between the length of time your baby has been developing and your 'official' week of pregnancy. We haven't gone crazy; there is a method to our madness!

We actually calculate weeks of pregnancy by counting from the first day of your last menstrual period, which we assume was exactly 40 weeks before your due date. As you don't ovulate (and therefore can't conceive) until approximately two weeks after the start of your menstrual cycle, the length of time that your baby has actually been developing is two weeks less than the number of weeks you have been officially pregnant. To put it in a more straight forward way - when you reach your 40th week of pregnancy your baby will only have been developing for 38 weeks.

This is a method commonly used to calculate EDDs by those in the medical profession, as for most it is usually much easier to recall the first day of your last menstrual period than to know exactly when you ovulated. So, it’s much simpler for everyone to count forward from their last period, although this does mean that technically for the first two official weeks of your pregnancy you weren't actually pregnant - bizarre, but that's why there is a difference.

 

[frankie247]

When you have your 12 week scan they will give you an accurate date of how far you are and when you are due

 

[mrs_bump]

Thanks for your replies ladies, it makes it clearer! xx

 

[Missylouise]

They are so confussing when they magically add two weeks wish they would make it bit more clear when they tell you EDD X