Scan date confusion!!

Hi all, wondering if anyone can help... I had my scan today, and although quick it was the most amazing feeling, knowing that my baby's heart was beating and that baby was healthy and okay. The only thing I'm confused about, is the woman said that i was just about 12 weeks, which is correct to my caluculation and that of how my doctor calculated it, as they do it from the date of the first day of your period right? So realistically i should be about a week or so behind (as ovulation takes place about a week or so after your period). What I'm confused about, is if i count 11 weeks and 6 days back, it takes me mid week to the week i was on my last period... which is obviously not when i conceived. Can someone help me plz I'm getting quite confused and aggitated by this now... Thanks, Momtobe.

Snap!!!

hi i'm 29 & am in the same boat as you. i am devestated as i am not a tart at all!!! basically i slept with X on the 13th dec & then Y on the 28/29th dec & 6th jan....i found out that i am pregnant on 30th jan! my dating scan is the 14th feb....i am so anxious as i dont know if the scan will be accurate in dating my pregnancy. i dont want an abortion but i also dont want a pregnancy when i am uncertain of the father???? i feel so helpless. if my scan date says im 12 weeks it'll b Xs but if the scan dates at 10 or less it'll b Ys....do you think it's reliable enough??? please respond you're the only one who knows what im goin through x

Not always accurate

scans are not 100% accurate. they measure the fetus and uterus and go by those measurements. when i was 9 weeks, i went for a scan and it said i was 7 1/2 weeks. my last scan(20 weeks) they said i was 21 weeks. you should be getting another scan around 20 weeks. i would go by that date.

You ovulate about 2 weeks after your period starts

Or midway thru your cycle, if you cycles are longer / shorter than 28 days.

"must be good to know everythings ok."

Scans arent always accurate. The mother always knows best (that is if you have been alert of the changes in your body....ovulation signs/implantatation signs /early pregnancy signs etc).

The day of conception is not necessary about 2weeks after the day of your last menstrual period (ovulation).It depends on each person's cycle.....and not all woman have the same cycle.

The scan usualy measures the baby' parts.....depending on how the feutus is growing (not all grow the same) the doctor can estimate the age. All these dates are estimations. My doctor once said you can have two kids concieved on the same date but have different scan readings.....see!

If one does not know who the father is whether its X or Y........using the scan readings to determine this may not be accurate. Rather wait till the baby is born and do a blood test.