How on earth do get a date 3 weeks out?

I assuming this doesn't happen too often. I know term is anywhere from 37 - 42 weeks as the dates can be slightly out, but a friend of mine was told a date 3 weeks early!
I'm assuming she may not have had regular AF, or O'd very, very late, but, wow!

Ok I'll explain. A friend of mine, accoring to original dates would now be 42 weeks.
She was due April 30. 12 days later, nothing has happened, so obviously induction was discussed.
She was booked in, but then started to panic about it. The idea of induction scared her. So she asked her ob to do a scan to see if the baby was ok to wait a little bit longer.

Well, during the scan its revealed that her due date is not April 30, but the end of next week...around May 21!

How on earth could you get to whats thought to be the end of a pregnancy & have noone realise?? She would've had at least the one scan. The morphology scan, which you would think, with the detail it goes into, that something would've been picked up!

I'm glad she questioned her need to be induced, or the poor bubba would've been here anywhere from 3 - 5 weeks before he/she was ready!

I'll be asking who her ob is next time I see her. On a plus side, she's alot more relaxed about the whole 'overdue' thing now & doesn't have anything to panic about.

Using a scan at such a late stage during pregnancy is extremely inaccurate and cannot give an accurate due date. To get an accurate due date during a scan, you need to go before 10 weeks (roughly). Even at 12 weeks, the dates will be out.
The due date would have been discussed prior to this, either by her gp, OB or midwife. There has to be an 'agreed due date'. Unless she wasn't seeing anyone until now. So if her dates are according to the first due date of 30/04, then that would probably be the agreed due date. According to the scan, but might appear to be small, hence why they are saying she's not 'full term' yet, however like I said, this can be very inaccurate.

FWIW: with this pregnancy, it appears I ovulated really early on in my cycle, and my dates are out by 12 days according to my dating scan at 6 weeks.

Yeah, thats why it doesn't make sense. If she was going off LMP dates, then she'd have some idea of an EDD.
If she wasn't going from LMP coz she wasn't sure, then you'd think she'd have had a scan to get an EDD that way. I know she's been seeing someone since the beginning. Even for a scan to get the dates a whole 3 weeks out seems a bit extreme to me. A few days, to a week, yeah...
Would it be safe to simply say the baby isn't due for another week, when its 3 weeks later than expected, without keeping a close eye on things? Would weekly check ups be enough to know that everything is ok?
& yes, I know that at this late stage, the size difference can be huge. She's not a very big person & it wouldn't suprise me that she'd be carrying a smaller than average baby. So how can they just know this? I'm just worried that the ob is saying that she's not due yet coz of the babies size & just dismissing it, not making sure the baby really is safe & happy in there. I mean what if she does go past dates, but her EDD really was earlier than they now think & things do start to go bad? I dunno...I can't help but worry. I don't have much faith in the obs I've seen here, which is why I'm having my baby here at the local hossy under my gp's care, rather than going to the newer, nicer hossy again.

Wow seems like a massive change to dates so late... I was going to ask as well did she have any early US, because they would be definitely much more definitive than anything later.1-2 weeks is more common but 3 is quite adifference, just look at all the different sizes the bubs are that are born on BB the range is massive yet they can all be about the same gestation!!!

It makes me wonder how early she started with the OB's and what they used to do all the dating etc at the start and how the bubs size was at the 12 and 20 week scans....

If it were me, for peace of mind I would be getting ultrasounds done every couple of days just to check that everything is going ok with bub (placenta etc). Maybe she can request that from her OB?

Seems a bit odd to be changing the due date at this late stage. I presume that everything looked ok at the scan, though?
I'd want to monitor things pretty closely at this point, as Jodi says. Hope she doesn't have to wait much longer

LAte scans can be really inaccurate though.
If she didnt know her dates they surely did a dating scan earlier on?

With DS1 I had the two "normal" scans at 12 and 19/20 weeks, both confirmed my EDD base on LMP to within 3 days.
I then had to have a scan at 36 weeks, which said my EDD was FOUR WEEKS earlier, and infact the next day.

But my dates werent wrong, I just had a 10lb_, very long bub.

Has she had monitoring done for placenta function?

I think thats what the scan would've been. For placenta function.
I don't know. I really can't get my head around it. We aren't very close either, so I probably won't see her again til after bub's comes.
I just hope & pray that they are right & the baby is ok at the end of it all...

Just thought I'd update, she had her baby girl, Shaila, a few days after I posted this.
Perfectly happy & healthy baby :)

That's great to hear! Thanks for the update and congrats to your friend :)

Wonderful news :D thanks for letting us know!