Measuring a week behind on ultrasound

[Anonymous]

Does anyone have experience with measuring small on ultrasound in the first trimester. I am 10 weeks 5 days according to my LMP but the u/s says 9 weeks 5 days. There is no way I am wrong about the date of my last period (wrote it down on calendar), and got a BFP on day 28 of that cycle (although I guess I could have ovulated later than day 14, since I took an Early Response test).

Should I be worried that baby is not growing as he/she should?

[Anonymous]

It is possible that you ovulated and conceived later. My cycles were around 32 days, but I conceived around day 21--and I know this because I was out of town until day 20 so it could't have happened earlier. Thus, i measured behind according to LMP, but it matched up with my sense of the conception dates. And since the baby has been growing consistently since then (now near the very end), they used the newer dates (confirmed on 20 week).

I hope this is the case with you and that everything goes fine, but there's not much you can do for now. maybe you can get another u/s sooner than 20 weeks?

[Anonymous]

Are your cycles normally long? If so, that could easily explain the difference. At my 20 week ultrasound I was measuring 5 days ahead - I'm positive this is due solely to the fact that my OB was counting from my LMP and I have short cycles, and ovulate early. I was charting and so I know what day I ovulated and it by that count I am 4 days further along than my OB calculates using LMP - which means I am really only measuring 1 day ahead. Confusing, I know! Hope that made sense.

[Anonymous]

There's a 5 day margin of error on early u/s measurements, so given that you don't know exactly when you ovulated, I would not worry!

[Anonymous]

No, really do not worry! There are so many benign reasons for this! Just look forward to the next ultrasound!

[Anonymous]

I measured a week behind right up until I gave birth. I had a healthy boy! My cousin in law is also measuring behind. I don't think its that uncommon.

[Anonymous]

I measured a week behind early on (first appt, so around 8 weeks, I think). I was charting and using ovulation sticks, so I KNEW when we'd conceived within a day or two. I'm now at 34 weeks and everything looks great. When I did reasearch on it, mostly what I found is that measuring small, while not great, isn't alone a clear indication that something is wrong. Measuring small and a low heartrate (I think it was under 100 BPM) is when there's a real concern (I actually think any time there's a HB under 100 it's a concern, regardless of measurement). If your OB got a HB, ask to see what that was. Also, they should definitely follow up in a week or so. At my next appt a week later, the baby measured much more on target.

I hope everything works out well for you and your baby.