The pelvic shape may be secondary to fetal rotation and flexion into the pelvis, but size and shape do take a role in childbirth. The fact that obstetric surgeons switch to cesarean surgery if the baby doesn’t fit doesn’t mean the rest of us are ignorant in ways to support the individual size and shape of the pelvis.
Though I’ve only been interested in a woman’s pelvic shape and size occasionally, not even annually when I was attending births regularly, there were situations when an interest was indicated.
The woman with a gynecoid pelvis often finds that labor itself will eventually get the posterior baby rotated to any of the anterior positions, or in some cases, gives birth to a posterior baby.In a woman with an android pelvis, if her baby at the end of pregnancy is rather large (for her) and in the posterior presentation, I note that the forehead can settle into the triangular shape of the anterior inlet making rotation next to impossible unless the round ligaments and broad ligaments can be loosened (first time mother issue and older mother typically) and the baby helped to reposition to the LOA then the baby may never engage, even with labor. We start with this mama in 2nd trimester to achieve a dynamic balance so that her baby comes into the brim in the LOA position.
The woman with an anthropoid pelvis will start labor with either an OA baby (if engaged) or a direct OP baby and in either case the baby may rotate on the pelvic floor or may be born without any need to rotate. Could these be the women with the 3-8 hour posterior labors that find that all the fuss wasn’t applicable to their experience?
In a woman with a platypelloid pelvis, her baby does need to get into the LOT position, usually with chin tucked in flexion, to enter the pelvis. Labor can be days shorter if this is achieved before labor rather than through long, hard, frequent contractions.
You see that the woman with the android pelvis, the fast sprinter or easy runner, may have an issue if her android pelvis runs on the small side and her baby is large (maybe she drinks more than a quart of milk daily and such foods that grow large babies). The woman with the platypelloid pelvis (only 5% of all) will be very interested in helping baby face her right hip (LOT or LOL in UK) to start labor. Overall, 65% of OP babies rotate to the OA by the end of labor. But starting labor in one of the anterior positions, or at least with a tucked chin, does make a difference for some pelvic types.
Most women can go into labor confidently without knowing whether their pelvis is round, oblong, or even triangular, but there are times when a little knowledge helps women prepare for labor and their providers pick techniques and exercises that promote rotation and descent rather than choosing common techniques at random, simply because they usually work and not knowing what the woman they sit with needs for this long labor.
Labor is worth it.
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Thank you for continuing to teach about the importance of knowledge of the mothers pelvimetry and position of baby prenatally! I have talked to too many women through ICAN meetings who had cesareans because their care providers did not understand these concepts. It is still important for midwives to be knowledgable about these things and we can continue to help the motherbaby without making the mother feel her body is inadequate! Doesn't the medical model do that enough?
Mary, I agree, we can talk about these things with an aim of empowerment, not "blame" or exaggeration. Whether medical or midwifery, extreme statements can hurt. When knowledge comes with kindness we can reach empowerment.
Dear Spinning Babies Lady,
Thank you for this article. I am particularly interested as I was told by my doc during the second cesarean that I have an android pelvis and a very prominent promontory and that I cannot birth vaginally.
We are now expecting our third child (35th week) and I am still dreaming of a VBA2C! (though the doc has excluded it)
May I ask you whether you know about this problem? Do you have any advise in order to move back the promontory and increase the pelvic diameter?
Is the LOA position the only possible position in order for the baby to engage?
Thank you in advance for your answer!
I'm certainly stuck feeling like my body was inadequate for labor. Midwives allowed me to labor as long as I wished, and at 3 days I called a halt. Never got past 6cm though the labor was mighty. C section allowed the birth.
I think every cell in my body thought it was going to die, and I am so grateful for the intervention. But I wish I knew what to do to have a vbac with a body that I can't trust.
Dear Spinning Babies Lady, thank you for this article. I feel particularly concerned as my doc told during my second cesarean that I have an android pelvis and a very prominent sacral promontory and will never birth vaginally. I am now 35 weeks pregnant with our third child and still dream of a vaginal birth. Have you heard of this problem? What would you advise me to do in order open my pelvis as much as possible?
I had an emcs due to brow presentation in labour, baby was OA throughout the whole pregnancy, went OP during labour then got stuck. The consultant mentioned this could be down to pelvic shape, however went no further into the explanation other than going into details of a planned cs. I don't want another cs, the anaesthetic failed and it was one of the most traumatic experiences in my life, I desperately want more children however have a fear of the same situation being repeated. How would I go about finding out my pelvic shape?
You might look at https://www.spbmembership.wpengine.com/more-info/anatomy-for-fetal-positioning
Optimal Fetal Position, your pelvic balance and mobility, and having a healthy baby, not too small and not too big, may be more useful to you than the average woman.
I have been diagnosed as having an android pelvis, and I desperately want a natural birth. I have had 2 c-section (wasn't diagnosed until after the 2nd c-section, sectioned de to 3 dad labor and failure to progress). I'm terrified this labor will end the same way. Is there any advice you can give me? I really don't want my last baby to be a c-section too, if it can be helped at all.