Can a foetus catch up (size wise)

[pinkdressinggown]

Hi all,

I'm 8 weeks pregnant and went for an early scan the other day. The foetus was measuring only 6 weeks but did have a heartbeat.

My dates are definitely accurate (I know exactly when we conceived) - does anyone know if a foetus that measures so small can 'catch up' and be ok? Or is it a sign of a failing pregnancy?

The sonographer says she thinks the heartbeat will stop within 2 weeks, but I just wanted to see if anyone had any positive stories from a situation like this. Thanks in advance.

Depends on how accurate your dates could be. Only Ivf pregnancies have any kind of accuracy when it comes to dates - all other methods of ovulation prediction etc has a lot of room for error.

Thanks @GrumpyHoonMain - my dates are definitely accurate, and I know the foetus is smaller than it should be. I'm more asking that, given that the foetus is measuring over 2 weeks less than I currently am, can they every catch up and be ok...

I had an early scan when I knew I was ten weeks and he measured as 7 weeks, but our dating scan showed he'd caught up and was measuring spot on for 12 weeks.

I guess they have growth spurts which is why they don't tend to scan before 12 maybe?

It’s only considered a problem for an ivf pregnancy as everything else is considered inaccurate (sperm can live inside you for 5-7 days, you might have had an early loss and then ovulated again a week later, ovulation kits only predict the time before ovulation not ovulation itself). If there is a heartbeat and it is in the normal range then your dates are probably wrong.

Hi @pinkdressinggown. I’ve just come across your post as I’m searching for answers for the exact same thing and wondered how things turned out for you? I went for an early scan today at 9 weeks and was told the pregnancy is only measuring between 5-6 weeks and there’s an irregular heartbeat but she would give me no other information or answer any of my questions, I’ve just been rebooked for another scan in 2 weeks time but I’m obviously very anxious. Like you, I’m sure of my dates and have a picture of my positive pregnancy test dated 15th January. I’m just so confused

I think a lot of the dating comes down to position of the fetus and precision of the sonographer. At my first scan the fetus was measuring a few days smaller than I knew my ovulation date to be. At my second scan it was measuring a whole week too big. They are just clicking little lines on the screen, roughly dotting from head to rump. If you watch them do it, it's very imprecise and is highly affected by how the baby is lying. I don't put much stock in it give or take a week or so. If your heartbeat is normal you might be ok.

It can go either way when they measure behind.
I had an early scan with our twins, 6 days behind lmp with hb's at 8wk, they caught up on growth by their dating scan.
My last pregnancy baby also measured 6 days behind lmp with hb at 8+3wk, mc it at 9+3wk.

I know there are lots of positive stories but I have had 2 miscarriages when both times they said the measurements were smaller than they should be (once by a week and once by 2 weeks). They were probably around the 8 week mark but I cant really remember for sure now.

I dont want to be doom and gloom as I know lots of people do go back and find that they have 'caught up' and I know that the measurements must be hard to do at that stage.

Hope all turns out well for you.

Thank you everyone. Every bit of information helps x

My scan measured 6 but I know dates should be 7, and sure enough at their 12 weeks I was moved to my dates and told 13 weeks. I believe it’s quite common pre 12 weeks as foetus is v v small so measurements not always that accurate