head circumference - starting to freak out

Family genetics (from both mine and DH side) do not do me any favours!!!!! Both sides are known for big heads and big babies

DD was born at 30 weeks with a HC of 27cm, by the time her due date rolled around it was 37cm and always above the 90th percentile line.

Now 29 weeks along with number 2 the HC measurements are starting to worry me.

20w 4d ultrasound - 17.5 cm
28w 4d ultrasound - 27.5 cm

basing on the same rate of growth - 1cm a week - I'm looking at a 39cm head to push out if I go to term.

When does the head become to big to push?

I don't think you need to worry. The measurements are just guesses, and any estimations they do based on those guess will be even more off. DD's HC was 36.5, and guess what? Didn't tear, not even a tiny bit ;) You'll be able to fit your baby out, very few circumstances arrive where there may be difficulty in achieving that. Try not to stress about something that will likely not even be an issue :hug:

Hugs Hun its hard nice you get to the end and start thinking about how on earth this baby will get out!

Bubs head has 3 plates which all overlapp as they start to move down the birth canal and when you finally push them out. So it's actually smaller then the plates move out and then you will see the head circumference.
Also ultra sounds are not 100% correct. So try not to judge it too much on that!
Have you watched many birthing videos? Check them out they may hel you prepare

Your body is amazing and it will be perfect birthing your baby! Good luck Hun you will be fabulous xxx

I second what Boomba said. Mother nature knew what she was doing when she made baby's head with 3 plates in it ;) My first baby was born with spectacular moulding of his head - he had this huge cone shaped head when he was born because of all the moulding. His HC at birth was 35cm. But at his first check up post birth is was 40cm. No way known could it have grown that much in such a short time.

As others have said, the head squishes down - it's designed that way on purpose.
My 2 were born with HCs of 35cm and 37cm. They come from a long line of big heads :) (In fact, I'm rather proud of the fact that my daughter's head is the average size for a 3 year old)

The other thing to remember, is that scans are notoriously inaccurate. It's quite plausible that your baby is perfectly well formed, growing well and will be the right size for you to birth.

I had two fathead babies (for their gestations) and I'm still in one piece ;) I'll admit that I did tear pretty badly with DD, but I attribute that to having an epidural and pushing past when I should have.

The others are right, the plates slide over each other to make the head mold better. That's why the majority of vaginally-birthed babies have funny shaped heads :lol: Thats something else that makes me think I pushed to hard with DD, she had a normal shaped head and I don't think I have her head time to change shape...

Thanks everyone. I know its easier said that to stress out but i will - guarantee!!! My cousin had a 41cm head at birth, DH had a 38cm and i had a 37cm. No one (unless born early) has had anything less then 37cm, or under 8 pounds!!!!! But hey if my grandmother gave birth to 5 fat head big boys over 40 - 60 years ago a i guess i can to (although she did think i was clever going early with DD and not push out the big baby)

Babies head are moldable and flexible. Your cervix will dialte to 10cm and you will birth your baby. When you are in labour you are not gooing to be able to tell the difference of afew cm when you are pushing your baby out, it will still hurt. I had some minor tearing when I birthed DS1 who was 6 weeks prem, DS2 who was term slipped out, no tearing.
I'm sure you will be just fine, good luck.