Brim measurements / optimal birth position

[Evie76]

OK, so you'll have to excuse my idiocy.

What EXACTLY are the brim measurements? Last week the baby was 5 fifths above the brim, now he is 4 fifths.

Is the brim the cervix and the birth canal measured in fifths?

I know the baby is very low as he is now pressing on my right pelvic bone quite hard and has only been doing so the last couple of days. So, I reckon he's dropped significantly.

My other question is, am I correct in thinking that the optimal birth position for the baby is with their back against one of your sides? I've heard if the baby's spine is aligned with yours, you are going to have back pain during birth.

Jellybean's back is against my right side - very convincingly.

[Taurean]

Not sure about the 'brim' measurements but here's some info for you:


What's the best position for birth?

The best position for your baby to be in when you go into labour is head down, with the back of his head slightly towards the front of your tummy. In this position, he fits snugly into the curve of your pelvis and it's easy for him to move gently down during labour. When he gets to the bottom of your pelvis, he turns his head slightly so that the widest part of his head is in the widest part of your pelvis. The back of his head can then slip underneath your pubic bone and, as he is born, his face sweeps across the perineum, which is the tissue between the back of the vagina and your back passage.

Your midwife describes a baby who has the back of his head towards the front of his mother's abdomen as being in an ANTERIOR position. Labour is nearly always shorter and easier if the baby is anterior.

[~TT40~]

ok...now this is the one part i have trouble with working out...hehe...but I'll give it a go and anyone can correct/add on please!!!

Basically when bub starts to "drop" it is doing what is known as "engaging" which is basically where its head enters your pelvis.
To measure how "engaged" bub is, or how much decent bub is making through labour they do a thing refered to the "station" bub is at. This is measured two ways (which is what confusses me).
both ways they devide the plevis into 5 segments, or 5 fifths.
the first way, which I think is what you are talking about Evie, is where they take reference from your brim, which is the pelvic brim, basically the opening to your pelvis. this is then said to be 0 and depending how far above or below bubs head is from your brim is how many fifths, for example if bub is already engaged and below your brim just a tiny bit would be 1/5 engaged, or if bubs head was completley within your pevis it would be 5/5 engaged.
The second way they measure can only be determained from doing a vaginal exam (or 'internal' and this is where they use your "spines" (little bits of your pelvis that stick out) as 0, if bub above the spines it is refered to as -x/5 or if bub is below your spines it is + x/5. with this one bub can have 2 numbers.....like if bub is -2/5 (so 2/5 above your spines) that is the same as being +3/5. I think it is just personal preference with one ppl say...
does that help? now like I said this is one of the areas I really struggle to get my head around, so might not be 100% but if someone knows please correct me!!!!
hope i explained it for you....
=P

p.s so basically bub being 5/5 above your brim means it isn't engaged yet, meaning it's head isn't in your pelvis. 4/5 means 4/5th of bubs head is outside the pelvis, and 1/5 of its head is in your pelvis =) bubs getting into position =)

[Evie76]

Thank you Teirae.

I think my brain just collapsed like a big ol' souffle..............

I do get it now. So, I wasn't far off the mark. Bubs is definitely getting in to position - and he's doing it come hell or high water!! Believe me!

[~TT40~]

I feel like my brain collapses every day!!! =P glad it sort of made sense =)

[earth_99]

p.s so basically bub being 5/5 above your brim means it isn't engaged yet, meaning it's head isn't in your pelvis. 4/5 means 4/5th of bubs head is outside the pelvis, and 1/5 of its head is in your pelvis =) bubs getting into position =)

That's what my OB explained to me when I asked him that exact question last week!

Also, wrt position of baby - my understanding from birth classes is that it works best if the baby shifts around as it moves through the pelvis - for the top opening to the pelvis, it works best if the baby is facing the left or right side. As the baby moves further down (through the second part), it works best if the baby is facing forwards/backwards. This is due to the different parts of the pelvis having different dimensions (ellipses but with the long part facing different ways), and matching those dimensions to the babe's head shape.

But when it comes to birth, it's best if the baby faces backwards - and most, but not all, do. If the baby is facing backwards at birth, you can end up with "back labour" (ie. more back pain) and can be slower and more difficult.

[Evie76]

thanks Earth.

I DO NOT want back labour - see belly buddies conversation!! I'm freakin' at the moment as is. The prospect of that is painful in itself. I didn't have it last time, just felt the cervix opening (yay! That was fun!), but I've "heard" back labour is not fun at all.