Ultrasound today! Measuring ahead! Question!

[quinnNjesse]

So my LMP was may 20. I ovulated on day 11, proven both by an OPK test plus a BBT temp spike the next day. According to my calculations I'm 12.5 weeks. Tech did numerous measurements and says I'm 14 weeks. How can that be?

I'm doing the IPS testing (u/s and blood work) and I'm concerned about how this will effect my results?

[crunchymom2b]

DDC, you could have had an early implanter. Or human error, the measurements could have beena tad off. Regardless things sound great!

[abhernandez]

Or maybe baby hit a growth spurt? I measured 8 days ahead on my last u/s (the nt scan) but I know my dates are right as baby measured close to my lmp date for both my 7 and 10 week u/s. And my edd didn't change. I think u/s stop being the best for precise dating at around 12 weeks.

[rachaeljohnson]

yes, genetics has a role now...my kids always measure ahead starting in th 2nd trimester. Are you or dh tall?

[almostcrunchy]

I have always heard that ultrasounds are only accurate for dating when done before 10ish weeks

If you are certain about your dates, then I'd say they are accurate and to disregard the dates given at the ultrasound.

[quinnNjesse]

Originally Posted by rachaeljohnson yes, genetics has a role now...my kids always measure ahead starting in th 2nd trimester. Are you or dh tall?

Ryan is 6"1', I am 5"7.5

I guess that's tall...

[quinnNjesse]

Originally Posted by abhernandez Or maybe baby hit a growth spurt? I measured 8 days ahead on my last u/s (the nt scan) but I know my dates are right as baby measured close to my lmp date for both my 7 and 10 week u/s. And my edd didn't change. I think u/s stop being the best for precise dating at around 12 weeks.

SEE that's what I'm thinking. I know my dates are right....of course I don't have two other u/s to compare to, this is the first....

I'm trying to research the accuracy but so far it's a lot of info to go through.

I'm sure it's fine, but either way I will call my midwife tomorrow anyways.

[My_Tree_Grows]

U/S are only considered accurate for dating purposes before 12 weeks, as mentioned. Also, the earlier they are done, the greater the accuracy...so that if one had an U/S at 7 weeks then that is the estimated due date which would be used, even if one subsequently measured ahead at an 11 week U/S. Yours was a bit too late to be taken very seriously, mama, but given that you know when you ovulated, the point is moot for dating purposes. Your midwife will likely keep your original EDD...and if she suggests otherwise, then consider arguing for it. After all, the later your EDD, the lower your odds of being pushed into an unnecessary induction when you might not actually be 42 weeks yet, KWIM?

With the NT test, the normal range of up to 3 mm is the same whether you're 12 weeks or 13 weeks and 6 days; it's in the earlier 11-12 week that a lower range up to 2 mm would be considered normal. So your results are unlikely to differ based on a longer crown-to-rump length. Ask the midwife for the actual NT number, if it's more reassuring to you.

And of course...the IPS is not a diagnostic test. It provides the odds of different possibilities only, not the definite genetic condition of your baby.

[rachaeljohnson]

yep, we are 6'3 and 5'10 so i am guessing it's genes at this point possibly even combined with a tiny bit of human error.

[karlitacat]

I've heard that babies grow at the same rate until a certain point... which is one of the reasons why my office does an early ultrasound (like around 8wks) to determine the age. Afterwards, they don't all measure the same.