HC dropped from 40th percentile to 8th

[Emmamaeee]

Hi,

I’ve been having growth scans every 3 weeks due to low papp-a. My 28 week growth scan went really well with baby measuring on the 50th percentile with his head on the 40th. My 31 week growth scan didn’t go well and the measurements show his head on the 8th percentile. Nothing was said about this or mentioned afterwards, even the consultant didn’t mention anything however I can’t help but worry about Microcephaly. Has anybody had any experience with growth scans and a drop in size?

I think the fact that your consultant didn’t mention anything is a really good sign, if they were worried, they would have said. 8th centile is still absolutely in the normal range, they only start to worry if the HC is starting to measure less than the 3rd centile. Maybe you could speak to your midwife and request an extra scan in a couple of weeks to put your mind at ease? I honestly wouldn’t worry about microcephaly just yet, I know that if babies are head down when their heads are measured, these measurements can be greatly inaccurate and it’s likely your baby is just fine 😊

I've had low papp-a when I was pregnant and similarly my baby didn't grow but for us it already started by week 20.

Ultimately I had to have a c-section by week 33 and my son was born on the 0.4th percentile.
The reason for me was a placenta which never grew enough and the c-section was needed as the umbilical artery had reverse flow.

Microcephaly wasn't ever mentioned as a problem and he didn't have it. My son is extremely healthy now, and in hindsight the doctors always were extremely honest and wouldn't have kept anything back.

It is extremely scary to go through but they have regular scans and check ups for a reason. If they are worried about anything they will tell you!

Hi

It is likely that your HC will be ok. I’d your consultant isn’t concerned that’s reassuring.
A HC less than the tenth is small and when we see that we yes we’d prefer it bigger. There could be reasons for this drop in measure , it could be operator dependent... maybe e wrong planar slice through the head wasn’t correct, maybe the baby was in a difficult position and maybe baby just has a small head because both parents have smaller head shapes ie you wear a small hat.

Good luck and best wishes

First thing is that HC needs to be on or below the 0.4th centile before a diagnosis of microcephaly (my first was below the 2nd centile) so it doesn’t seem like you have to worry too much about that.

With my second I had 8 growth scans which all predicted her to be about 3kg. She was 3.8kg! So these measurements are not and cannot be exact.

If they were concerned about it I’m certain they would have said however you absolutely should ask to be given more of an explanation.

I realise I said not to worry and that that is easier said than done but as someone who obsessed over every single measurement I can only say try not to because you can drive yourself a bit crazy. I hope your little one is ok.