Why not change my due date?

Question

I had a dating ultrasound because it was my first period since having my son and I had irregular periods in the past. The ultrasound tech said baby was measuring 7+2 and according to LMP I should have been 8+1. I know when I ovulated because I was tracking it and it makes more sense with the ultrasound weeks rather than LMP. When they called today to tell me the ultrasound results they said they were sticking with my LMP? Why?!

Answer

Same as you, I went in to my ultrasound at 8 weeks 1 day and baby was measuring 7 weeks 3 days. My doctor said they don’t change the due date unless it’s over a week off. So we kept it.

Answer

Generally speaking they only switch it from LMP if it's off by over a week. That being said I had irregular periods (ovulated between day 14 and day 32) so I was temping very regularly at 5am and know the exact day I ovulated. I told my doctor this and she was still going to go with LMP because it was 6 days off of scan but I felt strongly LMP was not accurate for me (ovulated day 23 bfp cycle) and we ended up moving it to date based on size which was half way between LMP and my ovulation date calculation. If you feel strongly that date is off by a week and don't want them thinking you are a week late when you are right on time later on I'd talk to your doctor and see if they can update the date to one you feel comfortable with.

Answer

If you know when you ovulated that’s more accurate.. it really doesn’t matter what they safe. It’s just a “guess” date anyway.

Answer

I was 4 days behind and they changed mine.. Who knows.maybe it differs with docs

Answer

I’m 4 days ahead and they kept mine the same

Answer

I was 5 days behind and they changed mine.

Answer

Once you’ve had a couple and it’s consistently measuring a week behind then they’ll switch it. It’s normal for it to fluctuate by seven days or so.

Answer

I think if it's less then a week difference they don't really change it.

Answer

At this early it could just be the baby’s growth rate, I measured a week behind my first scan but at my second had caught up to right on track. They’re probably waiting until you have another scan before changing your due date.

Why not change my due date?

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