How often do doctors screw up gestational age on early transvaginal ultrasounds?

Question

I had one done at what they decided was 8 1/2 weeks, saying my LMP was April 17th, I thought that was the latest date I could have had my period (I forgot when it was, thats why we had the ultrasond), but I originally thought it was more like the 4th of April.

Anyway, here I am at what would now be near 35 weeks, and the baby has been dropped and engaged since 32 weeks. No biggy, that happens all the time.

But at the 5 month ultrasound he was 1 pound 12 oz, when the average is about 13 oz. Thats like twice the size he should be. Okay, no biggy, that also happens, you know, different growth rates and spurts and all.

But here I am, with a fully dropped baby, and even when laying and standing I have feet under my ribs, and he's not pushing, its just where they are all the time (holy cow when he pushes under my ribs i KNOW it... its horrible... lol, and his favorite passtime). He's big! Or long..

It could be that iam farther along than they initially thought right? Maybe a week or so?

I have an appointment today and will surely ask.

Especially since Ive been having a ton of braxon hicks as the weeks progress.

nope, tested negative for gestational diabetes.

Big babies do run in the family... up to about 9 pounds... but honestly, if he's this big at 35 weeks, and hes going to almost double his weight by birth... God.. i'll be birthing a cannon ball. lol.

Answer 1

The one thing that I have learned from being pregnant this time is that it isn't the doctor that comes up with the gestational age when using the ultrasound. What happens is they take a series of measurements and this is entered into an equation. The major measure of gestational age in early ultrasounds is the crown to rump length of the baby.

This measures from the top of the head to the bottom of the bum. Before the 12 week or so, this measurement is a very good predictor of the age of the pregnancy as babies grow a t a constant rate. Once you hit 12 weeks on the rate of growth varies from baby to baby.

Most doctors will stay with the gestational age they get from the earliest ultrasound despite how the baby progresses in later months.

If big babies run in the family, that is probably the answer and the due date was accurate for the measurements at the time.

Good luck with you new linebacker. LOL

Answer 2

You must be having a boy! Only a boy would foot his mothers ribs. Seriously, it is possible that you are further along than originally thought, but the ultrasound is pretty accurate. It is actually the most accurate means of dating a pregnancy they have. This baby could just be big. Have you been checked for gestational diabetes? I know when I was pregnant, I found out that I had gestational diabetes when I had an ultrasound because they said the baby was macrosomic. When I got home from that appointment, I got the phone call that my bloodwork came back saying I had diabetes.

Answer 3

Usually, key word, they are pretty accurate when you first go in around 7-10 weeks because they can see what has yet to develope and what has taken place. They still be able to tell after that it's just a little harder because after that they are really just going off of how big the average baby should weigh and measure ect. And if they are off it doesn't sound like it matters too much, I mean you'll have the baby sooner than you thought and he sounds pretty healthy being so big already. I would definatly ask though at this next appointment, never hurts and you're paying the doctor to answer your questions.

Answer 4

Maybe you are just having a rather large baby...if your doctor hasn't mentioned anything in the previous ultrasounds is because they have a range for the weeks and maybe your baby is just big and in the higher percentile of development. I wouldn't worry too much about it, just ask your dr in your next appt. Good luck honey.