Why would doc change my due date?

[jackiefirsttimemom]

I was Due July 26th and my doc changed it to aug. 10th! I had my 20 week ultrasound, n he changed it when I saw him afterwards. I had an early ultrasound December 31st, n he said I was right on track. And I've heard that later ultrasounds in the 2nd n third trimesters aren't as accurate as first trimester ones. And I know my last menstrual was oct . 18th and I haven't had intercourse since November 11th. I'm 22 weeks and he said I'm a week behind, so 21 weeks, but why would my due date go out to Aug 10th from July 26th? He said we will find out the exact reasoning for my due date change at my next ultrasound this coming Wednesday. So is my baby measuring small? Do they go by baby's measurements as to how far along you should be?? Help!! Thanks!

[jackiefirsttimemom]

Oh and I did have an early ultrasound n he never questioned the dates. But thank u!!!

[RockRose]

I wish you the best,  Jackie.  It seems doctors don't ever just push out the due date because the baby is measuring smaller than gestational age - once they get a good gestational age from an early ultrasound,  they stick with it even if the baby isn't progressing in size like his peers.  

I think you'll know a lot more Wednesday,  and will have a chance to have your questions answered.

[jackiefirsttimemom]

I have an ultrasound this coming Wednesday with a specialist bc at my 20 week scan my doctor said they saw a small amount of fluid by the heart and said it could have been a shadow or something on the ultrasound but not to lose sleep over it bc it's a very tiny amount. N he said I'm a week behind according to my 20 week scan so I'm 21 weeks instead of 22 n that when I have the ultrasound with the specialist on Wednesday they'll see why the need for the change in due date 2 weeks out to Aug 10th. So my guess is they go by measurements of the baby? Maybe my baby is measuring small? I'm also a smoker and on methadone maintenance and my doctor knows this. He said when I have the ultrasound will see the reasoning for the ddue date change.

[RockRose]

I would really want to know what decisions your doctor plans to make about your new due date - for example,  does he intend to allow you to go weeks over your July 26 original due date if you haven't delivered?  This really needs to be worked out -

best wishes.

[jackiefirsttimemom]

And how is is possible I conceived the 18th if I had my period oct. 18th. I should have had my period

[RockRose]

I think you need to have another meeting with the doctor,  jackie,  and insist that you didn't have sex after Nov. 11.  Your new date suggests a conception date of around Nov. 18,  when you probably actually conceived around Nov. 1.

Since you've already had an early ultrasound,  it really does seem odd that he's changing your due date based on the baby being apparently smaller than expected.   That's really not how it works.

Best wishes.

[maw4389]

The earliest ultrasounds are the most accurate. That's odd that he's changing it.