Baby development.

Hello, so i am 4weeks from conception, but 6weeks from LMP...
So from which date do i go on for baby's development?
Thank you.

[AnnieBrooke]

You go by the medical way of counting.  I even have a book that says things like (in big letters) Sixth week and then in little letters (Fourth week since conception).  All the milestones for a developing embryo are listed using the medical way of timing a pregnancy.

[jess674]

You go by conception for the baby's development :)

[AnnieBrooke]

Maybe it depends on the book.  lol

[2B_expected]

Thanks alot, its pretty confusing at times :)

[AnnieBrooke]

I just checked my books, and Babycenter, and Parents.com, and they all use the medical way of counting.  So at week 1 they just say things like "Something exciting is about to happen!" and stuff like that, since obviously you haven't even conceived yet at week 1 counted the medical way.  But again, it may depend on the book.  The way you can tell is by looking at week 1 and week 2.  If the baby isn't even a cluster of cells yet, they are timing the pregnancy the medical way, by the first day of your last period.