Baby's head size

[Y Thingy]

This might be a stupid question. I was reading Aiden's birth record and it said his head circumference was 34.5 cm. If we assume baby's head is pretty sound and divide that by 3.1416, I get a 11 cm diameter for his head. I read somewhere before that baby's head is usually 10 cm wide so that's why we're "allowed" to push at 10 cm. Does that mean I got a big headed baby and explains my slow pushing? Well, I checked an online baby percentile thingy and head of that size is actually below average! Aiden's head was very very molded when he was born. I guess if he didn't have all those molding he might be average sized. But that would imply most women push babies out with a head way bigger than 10 cm. Am I making sense here?

I just don't see how he can be small headed. Most babies I saw have heads much smaller than his.

[*Jenn*]

Joshua's head was 33.5cm and I had no trouble pushing. It only took me about 10-15 minutes.

Maybe its because you have a smaller pelvis hence the very molded head.

[hedra]

11.76 cm across, here, for Gabe (pushed for just over 2 hours). And (ulp) 12.57 cm across for Brendan, and pushed for less than half an hour for him. Neither molded, by the way, and Gabe had a high cord wrap so didn't tuck his head, so he came down the largest way first. Brendan tucked his head. Bigger one was much faster, but also different head position.

Which leads to the answer to your question - the direction they measure for head size is the largest circumference, around the back of the head and across the forehead. The way kids usually come down is crown/back-of-the-head-first, which is the smallest circumference of their head. They aren't truly round headed, and with molding, even less so.

The other factor is that (IIRC) 10cm is not measured strictly, it is measured approximately. And that approximate also includes the degree of curve coming through the cervix. So, with a bigger-than-normal baby, the cervix might indeed be larger than 10 cm when they call you 'complete' - because they'll be checking to see if the edges of it have moved past the degree of curve-of-head necessary, not just the exact numbers. And with a smaller baby, you'll be complete at less than strictly 10cm, but again, the degree of curve of head coming through will tell them that.

With molding, most kids are about 10cm (or less) across when they go through, in part because that's the average size of the pelvic opening, and babies heads mold to get through that (my pelvic opening is, in my DH's eternal words, 'freakin huge' LOL!).

Pushing duration has more to do with overall baby position and stretchiness of yor tissues (and how much baby has to mold to fit - though there are a lot of factors that combine in different ways). Certainly little to do with the measured circumference, because that measurement is not taken on the same angle that baby went through your cervix.

[miche]

My son's head was 35.5 cm which is about 14in. I was told that 13-13.5in around is pretty average.

[missing]

Owen's head was about 13 inches - no problems here !

[hedra]

(realized that I didn't do the actual inches note - Gabe, 14.5 inches, Brendan 15.5 inches - both kinda big...)

[DoulaAmanda]

My dd's huge (and very molded) head was around 15 inches, and my own (posterior, even) was 16... big heads run in the family I guess :o

Fully dilated (aka "10" cm) is not necessarily 10 exactly, they do not go in there and measure with a ruler :o So for some women, it may be a little more than 10 and some a little less. The cervix has to be completely open (10cm) before you can push... as the baby comes down, it stretches even farther if it needs to. If you are not fully dilated when you push, it can swell the cervix and it has to re-open before baby can come through.