Monday, December 22, 2008

"She's got good birthin' hips"!

She’s got great birthing hips”! Have you heard that one before?
I see the following questions all over the net:
My hips are small, (insert measurement size) can I give birth naturally?
I know a women with really wide hips, and she ended up with a cesarean - what happened?
If you have big hips is child birth easier?
Can a woman's hips be too small for a vaginal delivery?

These are not dumb questions. The idea that a woman’s hip size has everything to do with her ease of birth is not a new idea. It’s been a way of thinking for centuries, and it’s hard to shake a long standing myth.

Let’s break this down. First we need a nice picture. Thanks to the 20th U.S. edition of Gray's Anatomy of the Human Body, originally published in 1918 - we can safely use the following pictures because they are now public domain.
You see those Micky Mouse ears on that pelvis? That is the ilium, and that is what we think of as the hip bone. Now the ilium comes in all different sizes. But the size of that iliac area does not have anything to do with birthing babies. When it comes to birthing, it’s the size and shape of that round hole in the middle of the pelvis that counts - but keep reading, because there is more to that than meets the eye. The main hole in the middle of the pelvis is called the pelvic inlet. This is where the True Pelvis begins. There is much more to the anatomy of the true pelvis, but I’m going to skip it, dare I bore you to death. The True Pelvis is what is measured during a medical assessment. Let’s pretend we are comparing two different women. The size of hip bones (the ilium and iliac crest) might be quite large, and in the other, they may be much smaller, but their pelvic inlet may be the same size. So we can’t go by the measurements of our waist - or the size and shape of our pelvis. But guess what else? Measuring the pelvic inlet is ALSO not a big help! Even with the help of x-rays, and presumably accurate measurements we cannot predict the passage of a baby through that pelvis. Here is it where it get’s *really* interesting.

What most people do not understand is that the pelvis is not an immovable structure. We tend to imagine the pelvis as something solid and some believe it is one giant bone. There are four joints that join different pelvic bones together. During pregnancy and labor the hormone relaxin softens and relaxes the ligaments that join the pelvic bones, allowing the pelvis to give and 'stretch'. Look at the above picture again - this time focus on where it says “pubic arch”. In between the two bones that meet there in the front lies a pad of cartilage. This is symphysis pubis. In some women there can become a pretty good gap there. It can be painful towards the end of pregnancy when this happens. However, my point is to show you that the pelvis can “open”. Look at the picture below and check out the ligaments attached to the various parts of the pelvis.


The story continues. There is one more thing we must consider. The baby. A baby’s head is made up of several bones - and they are made to overlap during birth. This is what causes molding. No one, not even a doctor, can tell a women how much the babies head will mold - or how much a woman’s pelvis will relax to accommodate that baby. The *only* way is to try it.

Women are told all the time that they have a pelvis that is too small. They end up with an automatic cesarean without a trial of labor, only to give birth to the next child - much bigger in size, vaginally. Just ‘google’ the many stories! The diagnosis of CPD (cephalopelvic disproportion - meaning babies head is too big compared to the size of the pelvis) is given out way to often - sometimes before the birth, and sometimes after a long labor followed by a cesarean. A long labor, and even a long pushing stage is not an indicator of a small pelvis/big baby. Often these same mothers give birth to their subsequent children who are much bigger. Labors stall for other reasons. This diagnosis gives women doubts in their bodies, and then they pass these doubts on to other women. A woman who is a size 20 and has a nice large hips is told she cannot give birth naturally to her 6 pound baby. She tells the woman who is a size 5, with ‘smaller hips’, and then this poor women doubts her ability to give birth. Next thing we know, we have women measuring their hips, and wondering if they will have a harder or longer labor - and they are scared of a baby bigger than X pounds.

I write this because there are so many women out there questioning their ability to give birth. I don’t know if doctors are afraid of lawsuits, or what - but why is there such an increase in this ‘problem’? I’m just really glad that there are women out there that go ahead and say “YES I CAN!”. It is because of these women that we know that this diagnosis is often wrong -perhaps to error on the safe side of a lawsuit.

11 comments:

susan said...

This is so, so interesting. I knew about relaxin and the ligaments, but I thought it had to do with the ligaments that hold the uterus in place. I didn't realize that hips had ligaments, too. This explains a lot of what I've been feeling for the past several weeks -- thanks!

~The~Birth~Teacher said...

Thanks for your comment, Susan! Yeah, that pelvis can become quite sore (and downright painful!) towards the end!

Elizabeth said...

So if this is true, how come my obstetrician has told me at 37 weeks that the baby is still too high (5/5 engagement) and that my chances of a natural delivery are slim. He has booked me in for a ceasar at 41 weeks. I know from a previous birth that my pelvic inlet is 11cms and pelvic outlet is 9cms and resulted in a planned ceasar. Different doctor this time saying similar things. Could I still deliver naturally?? Is it too early for them to comment about engagement??

~The~Birth~Teacher said...

Dear Elizabeth,

I'm sorry that I didn't see your post sooner. I know it's too late now, but let me just say this for you and others out there wanting to know the same thing. Your doctor can measure your pelvic inlet and outlet - and even if they get an accurate measurement, they cannot tell how much your pelvis will open during birth. It can open to up to 30% for birth. There is no guessing how much a babies head will mold to fit through your pelvis. No doctor can tell you this. Your pelvic inlet is completly average in size (average is 11cm). The average pelvic outlet is around 11cm as well. However, the pelvic outlet, if allowed to move freely, is wider front to back than it is side to side. That can create an additional 3.5 cm of space!

As far as the engagement goes: This is your second baby that hasn't engaged yet? If so, that is completely normal. First time babies tend to engage a bit before labor - sometimes days or weeks. Second and subsequent babies may not drop until active labor - or even the pushing stage! Completely normal :-)

ayshrizz wan said...

I am a mother of 2.5yrs old son whom I delivered through c-section.
Now going for a VBAC delivery,my Dr asked me for Erect Lateral Pelvimetry x-ray.my counts are:
Pelvic inlet - 10.8cms
Pelvic mid cavity - 12.1 cms
Pelvic outlet - 11.1 cms
Fetal skull biparieral diameter - 9.2cms
Fetal head is not engaged.

I am 36.5 weeks today and I was told yesterday by my dr tht I m unable to deliver normaly. I just believe I can.
Plz advise me something.

Kelsey Fry said...

I never thought about this when I was pregnant, I never doubted my ability to give birth to my baby. I think most times the mentality of the mother is why they "can't" give birth naturally. I knew my body was built and designed for this purpose so I would be able to do it. I had my first child in only 6 hours of labor, I was induced also because I was 5 days past my due date and my baby was "large" (8 lbs 13 oz).

anna said...

In USA doctors are C-section happy butchers. (thank your for-profit hospital system for that.) Elect a midwife who is more in tune with what a woman's/ baby's body can handle. (Yes, it still takes two to tango...birth is not just for mummy but for baby too..the little ones participate just as much!!) You may end up with a much more pleasant, and natural experience.

600ants said...

It's spelled womAn in singular. Also, there have been enough cases where misguided attemps to give birth the "natural" way led to loss of life which a timely cesarean would have saved.

When telling yourself that your body was built to give birth, you should also take into account that this "perfectly natural piece of cake" and related complications had been the most common cause of death in women until the beginning of the 20th century. Even today, only in the USA thousands of women die in childbirth every year. Just something to think about.

Smerby said...

@Kelsey Fry: "I think most times the mentality of the mother is why they 'can't' give birth naturally."? This mentality is part of the vast conspiracy of "pregnancy shaming" I see far too often from women. Some pregnancies CAN'T be done naturally; there's a reason why women used to die from childbirth much more frequently than they do now, let alone the children who died. What a horrible thing to say to your fellow woman, that it's somehow their "mindset" responsible for a combination of genetics, hormones and circumstances that no one can control.

Lisa said...

in 1998 I attempted to give birth naturally to my then 7lbs 8oz daughter and she got stuck ....apparently it was her right shoulder that got stuck behind my pelvis so she was pulled and has shoulder dystocia or erbs palsy.
FFWD to 2011 had c-section to have my son (8lbs) as they say my pelvis is too small to have a natural birth and now I'm 34 wks pregnant and schedulded to have another c-section in may 2014.
Really disappointed as I really would like a natural birth but I don't want another child getting damaged.

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