Doctor is telling me my dates are off? but im sure they are not???

Question

How accurate are ultrasounds whne done in second trimester. I had one done at 18 weeks. I calculatd 18 weeks based on my last period date and i knew for sure the date.

The doctor said i was about a week less thank what i was . I know its only a little but i am just curoius since i am positive when my last period was so how can I be off?

Just would like your advice on your experiences? First time pregnancy )

Answer 1

Chances are that it will not matter at all.  There are very few women that actually give birth on there due dates.  Some go early, some need to be induced because they are late.  A week is not really a major issue.  If it were me, I would probably go with the ultrasound. I have been in labour twice now, and I am only 32 weeks.  They stopped it both times.  Having babies can be a mystery.  Don't sweat the little stuff, enjoy being pregnant and focus on you because there will be no you once the little one arrives. Life altering but worth it.

Answer 2

Ultrasounds performed after the first trimester are less accurate, and there can be a normal degree of variance of about a week or so in either direction of the date based on the LMP. In the third trimester, the variance can be up to 2 weeks in either direction of the date from the LMP.

They will not usually alter your due date unless more than one scan shows growth significantly different (more than two weeks) from the LMP date. So don't worry.

Answer 3

It's based on the size of your baby, you could still be 18 weeks pregnant but your baby is just smaller than the average 18 week baby. The same thing happened to my friend, she originally was due the end of June, but after an ultrasound her doctor said it'd be two weeks later. The doctor was right, she didn't give birth until July 10th. Doctors deal with this everyday and they know what they're talking about, I would trust your doctor and just count on your baby coming a little later than you hoped. Depressing huh! :(  

Answer 4

when they do an ultra sound the measure the baby and see how far along they have developed thats how they tell how many weeks you. your due date might change a couple times before your actual date