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U/S dating

499 Views 5 Replies 4 Participants Last post by  Mrs.Floyd
I know it's not precise at anytime but what's the +/- in the second tri? Here's the deal, this pregnancy was a surprise, I knew my lmp but not when I O'd. I usually have 24 day cycles with O on day 10 but I was sick and not paying attention when I got pregnant. I had an early u/s to confirm the pregnancy at 5w 3d according to lmp and we didn't see to much, went back at 7w and saw a hb. Now this was all well and good and seemed to track developmentally with my initial due date of 1/18. Because of my complications I had a few more u/s done and babe started to measure ahead. At my 12w u/s babe measured with an edd of 1/11 and my peri has switched that to my edd. Now his edd doesn't really matter as he won't be delivering me but I'll be seeing my ob for the first time since the edd change on Monday. Now the 12w u/s should be +/- 7 days so even though babe was measuring due 1/11 instead of 1/18 that's still in the range of normal. I had another u/s yesterday and babe was measuring a bit over 21w and I should be 19w 3d is that still in the range of normal for u/s measurements and dating? I'm hoping I don't have to fight with my OB to much to keep my edd the later date since I am most likely looking at an induction anyway I would hate to induce a preterm baby using the earlier date. I just want to make sure I have all my ducks in a row when i talk to him. I'm hoping the development track we saw in the begining speaks for itself and this is a non-issue but just in case. And for those wondering all these u/s and measurements and appointments and probable induction issues are necessary I hate them but I need them. On an amusing note the tech doing the scan yesterday kept trying to tell me if we were using the 1/18 edd babies measurements would be right on and I'm thinking wait, you're using an edd that puts me 20w 3d pregnant babe is measuring 21w 3d and if we were using the edd that puts me at on 19w 3d measurements would be more on track??? Then they'd be two weeks off not just one! I think she was having an off day though.
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My question is what would you be looking at an induction for? I am not sure about your EDD, mine is also off from the u/s dates.

I would think an induction, if you had to be induced, would occur before you actually went into labor. So, if you were going to need an induction, I would think you would want to stick with the week earlier date.

But then again, I don't know why you would need an induction (that is already being planned 20 wks early).
Like I said in the OP the induction is necessary. I'm on blood thinners and the safest way for me to deliver is stopping the medication and then being induced. If I were to stop the meds and wait for labor I would be risking a blood clot and if I were to go into labor on the medication I risk hemmoraging. My induction will likely happen around 38 weeks so I'd prefer to be inducing a baby who is truly 38 weeks not 37. Which is why all this matters and I'm ready to argue the point with my OB tomorrow if need be.
Even two weeks off should be ok at such a late dating u/s. Plus, keep in mind, that those +/- are based on a 2 standard deviations, or 95%; this means, that 5% of all measurements don't fall in this curve. This is unlikely, but still possible.
The only reason that I asked about the need for induction is that if you HAD to be induced (and due to your medical condition, it is necessary), you would need to be induced before you go into actual labor (I am just guessing, but it makes sense).

The thing about the timing is that it COULD work against you if you insist on the later EDD. What if you were due at the earlier time? And then you could possibly go into labor before the induction date if they decided to induce based on the later date.

Very confusing, I know. I just gave up trying to figure out which date was correct and picked a date right in the middle as MY EDD. That way, if I have to be induced, I will be closer to accurate. My OB still has the different (and absolutely wrong and I can prove it but they won't listen) date.

Anyways, that was my solution. I don't know if it would work for you. However, you can always just not allow an induction before your choosen date, even if you have to fight for it.

Hoping all goes well for you.
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Personally, I would NOT allow the date to be changed based on a later ultrasound. The earlier the ultrasound, the more accurate the date, so I would stick with the original EDD and totally ignore the new date. Whatever point in your pregnancy you are considering inducing due to your medical condition, think about this - if you induce based on the 'revised' date, what if your baby *needed* the extra week of development he would have gotten had you gone w/ the original date? You obviously already have that on your mind.

I say stick to your guns. Tell your dr. that you are aware that ultrasound dates are most accurate earlier in the pregnancy (as he should be well aware too) and that you would like to induce on 1/4, when you would be 38 weeks to the best of your and his knowledge. Let him know that you do not feel comfortable inducing any earlier for the sake of the baby. Lay it all out there and see what he says. And if you don't hear what you want to hear, remember it's never too late to switch providers to someone who will listen to you.
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