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Due date math question :)

post #1 of 6
Thread Starter 

My OB's office called to tell me my due date was changed from March 9 to March 19.  I had an ultrasound on August 22, which estimated to baby to be due on March 9, and estimated me to be 11 weeks 4 days then.  I have to wait until October to discuss this due date change with my OB, so I am wondering if any of you think it is unusual for the OB to add 10 days to the ultrasound's estimate?


 There's nothing else I can think of as to why it was changed other than just a typo.  My lmp was May 28 and I had a positive home pregnancy test on July 1.  My lmp points to a March 4 due date, and since I am breastfeeding, I think March 9 is right.  If anyone likes the math and such, I'd love to hear your opinion :)  

post #2 of 6
Okay, hopefully my math is right here, but yeah, March 19 makes no sense to me based on the info you've given. In addition to the fact that you've been given no rationale for the change... According to a March 19 EDD, you'd have ovulated on day 29 of your cycle-- possible, but not likely, especially if your cycles have been anything close to regular and 5 weeks long or less.

More damning, that would also mean you got a positive HPT at 6 DPO-- highly unlikely. By the March 9 date, it would be a positive at 16 DPO, which makes a lot more sense.

I guess if I were seeing the average OB, I'd rather have them move my EDD later than earlier, as pushing for induction at "post dates" seems to be the bigger problem. But it would also stink if your babe came just a little on the early side (like 37 weeks) and they whisked him or her away for observation because they thought he/she was 35.5... Or something like that. Or you were told your babe was macrosomic for his/her age, etc... A couple days... Meh. But 10 days is really significant IMO. Hopefully it was a typo-- if not, I'd push for a GOOD explanation.
post #3 of 6
Thread Starter 

Buko, thank you for taking the time to answer!  At first I was thinking, eh, ok so I won't hear the post dates induction talk.  But I have had two out of four babes weigh right at nine lbs. at birth, so I definitely  want the due date mystery solved so my measurements won't be too off :)  I thought I must be looking at the numbers very wrong or going crazy, lol!  So, I am glad to hear someone double check the math with me!

post #4 of 6

I agree with Buko...  It is really really weird that they would change it with no explanation.  I always have a "due date" and a due date.  The first is what the docs tell me and the second is what I know based on when I ovulate.  Trust your gut.  :)

post #5 of 6
Must be a typo and they just added a one to the nine for some reason. My lmp was 28 May also and am also breastfeeding but because I was charting I know O was on 11 June. This puts my edd at March 3. When I went for an u/s on 25 Aug, I was measuring 12w4d so that would put less than a week between us, which makes Mar 9 a reasonable bet.
post #6 of 6

I sounds like a typo especially since they were unable to give you an explanation.  Your math is sound mama!

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