Baby measuring behind at 9 week scan

[Liese27]

Hi! I'm new to Mumsnet and guess I'm looking for hopeful stories as I'm feeling very worried about my pregnancy. I'm 38, have an almost 4 year old daughter and this is my second pregnancy. I went for a private early scan at 9 weeks 2 days as I'm not nearly as sick as I was with my DD.
According to my LMP I was exactly 9 weeks but according to when I ovulated I thought I was more 9 weeks 2 days. My baby measured 7 weeks 6 days at best with a heartbeat. The sonographer who is a good friend and very competent said that the scan is inconclusive and I'll go back in 10 days for another sonar.

The LMP method is not very accurate and has a well known error margin of +/- 2 weeks. Essentially LMP is saying you are 9weeks, but the scan is saying (rounding up) 8weeks. This is very common. One of the reasons they do the scan is to get a more accurate due date than the one the LMP method calculates.

It also could be human error. During the scan, the operator has to point and click at the image and then estimate length of the embryo. When they are so very small early on, just a hair breadth of mid-clicking can calculate out as several days worth of estimated age.

I would not worry. You are well within the LMP margin of error, a second scan will probably have a more experienced operator who can more accurately click and estimate the embryo size.

Best wishes and congratulations.

@PlanDeRaccordement Thank you for your reply and encouragement.

If you are sure on your ovulation dates then unfortunately It could go either way - in my experience measuring up to a week behind is ok but anything more than that hasn't progressed x

Don't give up hope OP, It may not be bad news.

I went for an early scan when i should have been 7+5 by LMP but baby measured 6+1 so 11 days behind.
I had a follow up 2 weeks later so should have been 9+5 and baby had grown proportionately to 8+2.

By the time I had my dating scan at almost 14 weeks, baby had caught up by a week which is pretty much spot on to when I think I conceived. I'm now 31 weeks.

Good luck!

@ivfgottostaypositive I'm so sorry that you've been through this and ha a negative outcome. This waiting game is really terrible.
I have regular 26-28 day cycles and normally a 14 day luteal phase. I get ovulation pain just before ovulation. This makes it hard because I'm quite sure of my dates. With my dd I only had a 12 and 20 week scan and was she measures spot on with my dates so I have no experience with this. Thank you for your comment

@sel2223
Your story gives me so much hope.. thank you and congratulations on your pregnancy. I'm sure you value and love that 31 week old baby all the more after such a worrying start.

I asked a similar question a few weeks back. I was measuring a week behind at my 7 week scan, but did see a HB. Many ladies had similar, then caught up in subsequent scans and all was well. The sonographer said that its still so small at that stage and easy to get dates wrong. Unfortunately, in my case I MC at 10 weeks, but the vast majority that had seen a HB had good outcomes. Here is the link below:

www.mumsnet.com/Talk/pregnancy/3886836-Early-scan-1-week-behind-experiences-when-to-have-NIPT

@Elouera
I'm so sorry to hear about your loss and thank you for the link.

Going by my LMP I should have been 13+3 when I had my 12 week scan, however baby measured at 12+2. I had a gender scan on Saturday and baby is measuring exactly as he should be from my dating scan.
It can vary so much, I know it's easier said than done by try not to worry.

@Foreverblowingbubbles18 Thank you, I feel like I'm getting a bit better at not worrying and trying to take things easy. My life has been very stressful the past couple of months. I'm so happy to hear your baby caught up. Enjoy your pregnancy!

I was worried when my seven week scan showed a six week embryo, but three weeks later at a "ten week" scan, baby was measuring nine weeks.

So hopefully all is well with your little one and they will continue to progress normally x

@Liese27 - hi, I’m a bit late to this convo but having similar concerns as you did, I’m just wondering how it all turned out? Looking for some reassurance. TIA x