Whose dates would you believe?

[Warby]

This has bugged me for almost nine years now, so please weigh in.

Way back in December 2003, DH and I were trying to conceive our first. It was our third month of trying. I wasn't taking temps or checking cm or anything like that. I had a 28 day cycle so made sure we had sex on days 13, 14 and 15.

My period was due on January 1. I didn't get it, so I took a test the next day. It was negative. I waited an entire week before testing again. Got a BFP on January 9. Based on my LMP my due date was September 7.

I had my one and only ultrasound when I was around 18 weeks. The tech told me that I was not as far along as I thought, that I was only 16 weeks and 4 days. My due date was bumped to September 17.

I remember disagreeing with this date change. I knew when my period had started. On the other hand, I plugged the new due date into a website that would give you a conception date. It suggested that with a due date of Sept 17, conception occurred on Dec 26. I remembered that DH and I had had sex that night so it is possible.

My water broke on September 3 and my daughter was born naturally on September 4. She weighed 6 pounds, 10 ounces and was 20.5 inches. Depending on which due date you go with, she was either three days earlier or thirteen days early. I have had three more children since (all boys) and they were born one day late, one day early, and three days early.


So....what do you think? Would you say my original due date was "right", or was the ultrasound-adjusted date "right"?

 

[babyhopes2010]

id def say ultrasound as i was due with my 1st on 17th sept but mc

 

[zanDark]

I'd go with the date of your LMP seeing as you gave birth around your original due date

Of course there are times when O has been delayed for some reason...but I don't think that happened to you.

Some of my baby's measurements during ultrasound put her at 23 weeks, but we definitely know when we conceived due to IVF no confusion there!

 

[Hunbun]

I would probably go with LMP.

 

[Bonnie11]

I'd go with ultrasound. It's common to ov earlier or later than you expect and unless you are charting/testing/temping you won't know for sure so I would be inclined to believe the ultrasound

 

[SurpriseMom2B]

I'd go with LMP, it is my understanding that as the pregnancy progresses US dates become less accurate. So since you were so far along at the US I'd go with the LMP, now if the scan had been earlier, say 8-12 weeks, I'd say go with it....but after about 12 weeks the babies start to grow more at their own rate (instead of at a normal charted growth), so it's quite possible your LMP was accurate and your babies growth was just off.

 

[Smiler82]

So if you have 28 day cycles your LMP must've been about 4th December? So if you did conceive on Dec 26th that would mean you didn't ovulate til CD 22 (approx). With a 28 day cycle that is basically impossible so there are two scenarios - either you conceived on CD 13/14/15 ish as you were aiming for or you were having a random longer cycle where you didn't ov til CD 22 ish. If your cycles are always bang-on 28 days and no variation at all (other than a day or so either way) then I think the U/S was wrong. I agree with the PP about scans becoming less accurate the later you leave it. So basically I think LMP is right and US wrong

 

[Louppey]

I'd go with LMP