Let’s talk about the pelvis (as it relates to women). In general, the pelvis consists of four bones (paired innominate bones, coccyx, and the sacrum) held together by ligaments. The size and shape of these bones have a tremendous impact on how a woman looks physically. Medically speaking, pelvic shape is classified using something called the “Caldwell-Moloy” system. There are four basic pelvic shapes:
Gynecoid • Android
Anthropoid • Platypoid
A gynecoid pelvis is oval at the inlet, has a generous capacity and wide subpubic arch. This is the classical female pelvis. Pelvic brim is a transverse ellipse (nearly a circle) Most favorable for delivery.The gynecoid pelvis (sometimes called a “true female pelvis”) is found in about 50% of the women in America. It is the “classic” form that we associate with women and has an anteroposterior diameter just slightly less than the transverse diameter. Lucy Lawless of Xena, Warrior Princess fame has a classic gynecoid pelvis. Women like this tend to look…like women. They are shapely and curvy. They tend to hold fat around the thighs more so than the mid-riff. They can have a flat stomach without really dropping body fat levels low enough to cause some “female problems.”
A platypoid pelvis is flattened at the inlet and has a prominent sacrum. The subpubic arch is generally wide but the ischial spines are prominent. This pelvis favors transverse presentations. Pelvic brim is transverse kidney shape. The platypelloid pelvis is very short (almost like a “flattened gynecoid shape”). Only about 3% of women have a true and pure pelvis of this type. Women having a platypelloid pelvis tend to carry a lot of weight in the lower abdomen. It’s very difficult for these women to have really flat abdomens without getting body fat levels down into the single digits.
Flattened gynecoid shape
An anthropoid pelvis is, like the gynecoid pelvis, basically oval at the inlet, but the long axis is oriented vertically rather than side to side.Subpubic arch may be slightly narrowed. This pelvis favors occiput posterior presentations. Pelvic brim is an anteroposterior ellipse, Gynecoid pelvis turned 90 degrees, Narrow ischial spines. Much more common in black womenThe anthropoid pelvis is very long and almost “ovoid” in shape. It is more common in non-white females (it makes up about 25% of pelvic type in white women and close to 50% in non-white women). Women who have such a pelvis shape tend to have “larger rear ends” and may carry a lot of adipose tissue/weight in the buttocks as well as in the abdomen. These women can have a flat stomach with some real effort (they may have to drop body fat levels down a bit lower than women with the other two aforementioned pelvis types, but it’s “doable”).
An android pelvis is more triangular in shape at the inlet, with a narrowed subpubic arch. Larger babies have difficulty traversing this pelvis as the normal areas for fetal rotation and extension are blocked by boney prominences. Smaller babies still squeeze through. (Male type) Pelvic brim is triangular Convergent Side Walls (widest posteriorly) Prominent ischial spines, Narrow subpubic arch, More common in white womenThe android pelvis (sometimes called a “true male pelvis”) is found in about 20% of American women. Women who happen to have such a pelvis tend to have “flat rear ends.” Many of the truly “waifish women” we see so prominently in modeling today have this type of pelvis. It’s not necessarily a good thing for a woman to have such a pelvic shape, as most of these women will end up having a Cesarean Section if they want to have children. Women with this shape of pelvis have virtually no real difficulty in achieving a flat stomach—no more than the “average male”—because their pelvises are shaped like an average male.
- Caldwell-Moloy Classification
- Gynecoid Pelvis (50%)
- Pelvic brim is a transverse ellipse (nearly a circle)
- Most favorable for delivery
- Android Pelvis (Male type)
- Pelvic brim is triangular
- Convergent Side Walls (widest posteriorly)
- Prominent ischial spines
- Narrow subpubic arch
- More common in white women
- Anthropoid Pelvis
- Pelvic brim is an anteroposterior ellipse
- Gynecoid pelvis turned 90 degrees
- Narrow ischial spines
- Much more common in black women
- Pelvic brim is an anteroposterior ellipse
- Platypelloid Pelvis (3%)
- Pelvic brim is transverse kidney shape
- Flattened gynecoid shape
- Gynecoid Pelvis (50%)
excellent info regarding pelvis shapes. better than wikipedia for the first time as far as i remember.
Thanks for your feedback.
this has been so helpful with my exam! Thankyou!
I’m so happy it was helpful. THank YOU!
THat would be a much more extensive article and pictorial tutorial. This was to get the basic information on pelvic types out there. Good suggestion of another blog though!! 🙂 Thanks.
Would an android pelvis be the least suitable for a pessary?
I’m sorry, I can’t definitively answer that. An android pelvis is more of a male shaped pelvis and even though some women do have this
rather narrow pelvic structure, a pessary could be used regardless.
In the description of the android pelvis, it states, “The android pelvis ( sometimes called a ‘true make pelvis’ ). Should that be ‘true male pelvis’ ?
Yes, I made the changes, thank you.
Tnx. for Good Explanations Keep it Up We Find More education Than Wikipedia
Thanks for your comment. Appreciate it.
This is fascinating. I am pregnant planning a home birth and my mother has voiced concern. She has always spoke about my birth (which after much difficulty became a C section) and having a “heart shaped” inlet, but has never put more to it than that. I’ve been trying to shed some light on if I might encounter a similiar problem; She and I both have *very* flat stomachs … this is the first place I have seen that mentioned. Thank you!
Chris: Thanks so much for sharing your story. It’s important to remember no matter what shape or size inlet or outlet of the pelvic cavity, there are tons of ligaments and tendons surrounding the bone structures that stretch and bend and open up like a rubber band because of the increase secretion of the hormone called, “relaxin”. So no matter WHAT type of pelvis you have, the body know’s how to labor and birth, without even thinking about it.
Which pelvis has higher chances of CPD
An anthropoid pelvis. Larger babies have difficulty traversing this pelvis as the normal areas for fetal rotation and extension are blocked by boney prominences. Smaller babies still squeeze through. (Male type) Pelvic brim is triangular Convergent Side Walls (widest posteriorly) Prominent ischial spines, Narrow subpubic arch, More common in white womenThe android pelvis (sometimes called a “true male pelvis”) is found in about 20% of American women. Women who happen to have such a pelvis tend to have “flat rear ends.” Many of the truly “waifish women” we see so prominently in modeling today have this type of pelvis. It’s not necessarily a good thing for a woman to have such a pelvic shape, as most of these women will end up having a Cesarean Section if they want to have children.
My son was born transverse and had a cone head and I was torn inside due to a platypoid pelvis. I was never told this would be a problem until delivery. I don’t carry a lot of weight in the lower abdomen as stated. Figures I am in the 3% that have this pelvis
Tracy: Most people will not talk about your pelvis unless you ask for them to tell you the
type of pelvis you have. Which they can discern from a vaginal exam. After you find out, then it’s important to do your research and discuss the options of ‘position’ during the labor / pushing / birth aspects in your birth plan based on the ‘type’ of pelvis you have.
So sorry you had to go through this… but as I tell all first time pregnant women, “You learn A LOT with the first baby. You learn what worked and what didn’t.” I wish you the best in your recovery and future births.
Thanks for this detailed information
I have some questions :
Will a small pelvic have difficulty carrying pregnancy for nine months?
After a year and a half recovery from femural ORIF, is it safe to get pregnant ?
It is best to discuss those questions with your medical caregiver. I can’t give you a succinct answer to either of those questions. There are many more questions to ask you before they can be answered. Good luck
with getting your answers from the individual you will be working with before and during and after your pregnancy.
Thanks. I found the above information and comments very helpful and informative.
does the type of pelvis affect posture?
THere are many aspects that affect the posture. Regarding this particular posting, I am focusing on childbirth. You will need to do further research regarding your posture being affected by other body structures.
I can… depends on what your specific question about your posture is. There are many different factors that come into play when discussing posture. There is no one answer for everyone.
Wow! Am exited to have found more and as a medical student and thinking of specializing in obstestric, I believe it will be of great benefit to me and to the many people i gonna share ma skills with. Thank you so much.
Happy you were inspired by this posting. All the best to you in your future work in obstetrics.
aftr a pelvimetry check which says inadequate plevis , is there any possiblity of having a vaginal birth? or is it better to just go for a C-section
Not with that birth caregiver. You will need to find someone who will SUPPORT your pelvis structure and the ability to give birth vaginally.
So useful and great thanks very much
I learned a lot about the pelvic
Thanks for your feedback. Glad you were able to gleen some new information.
Please can someone with Anteroposterior pelvic inlet diameter 0.95cm, Anteroposterior pelvic outlet diameter 0.95 cm and transverse diameter 1.22cm have a safe delivery (without operation)
Please I need an answer please is urgent
Speak with your medical caregiver. I do not give medical advice on this blog.
Thank you for sharing this information here, very informative. My wife delivered 2 days ago via C section bcos after prolong labor of 5days the doctor discovered that her pelvic is small and the baby was finding it difficult to lower down toward the pelvic, I guess something was preventing the baby from doing that. What type of pelvic do u think my wife have?
I can’t tell you what kind of pelvis your wife had from the comment the doctor stated. Hospital births are racked with not allowing the woman to walk around, squat, or push their babies out in any position other than an occasional side-lying position or on their backs. Then there is the conversation of being induced before the baby was ready to come? Or if they felt it was TIME for the baby to come. Lots of fear-inducing languages ensue in the birth field.
So sorry for the C-section. The doctor would have known your wife’s pelvis type because of the pelvic exams
before and during labor. They need to blame it on something other than themselves.
Infor so great! If doctors and ob/gyn don’t supply this info before girls, before they are women, it feels like USA is a 3rd world country. It is a disgrace. This should be all over every type of media and even women who dont want to bear children, should be hounding their representatives for action. Also cats are less safe for all women but pregant women too. Thank you for this crucial information!
I agree with you. The only ones who will make the change are the MOTHERS!!! They need to step into their power and ask questions, do the research and demand another way to labor and birth their babies!
Very clearly explained info! Wondering if you can share references for the percentages of women who have each kind of pelvis? Thanks so much!
Sorry, don’t even know where to get that information in that most birth caregivers are NOT interested in the shapes of women’s pelvis’s.
I learned a lot about the pelvic
This is very interesting information. I probably have an android pelvis, am just learning about this. I’m tall, have always had a flat middle section and flat rear end, as you said. I also had a “sunny side up” baby, which led me to this whole subject. I would urge women to find out if they have this, because it does indeed make childbirth very protracted and very painful. I wish I had known in advance!
Luann.. I am sorry for what you went through. IF you labored and birthed your baby in a hospital, they would have more than likely, put you on your back, strapped you to a monitor, possibly given drugs, and not allowed you to walk around, squat, kneel on the bed/gurney, etc. Because of your pelvic type… you NEEDED to be upright, in a tub, sitting on a birth stool or kneeling on the bed or floor so your body could support your ‘sunny side up’ baby to rotate and turn more readily.