Pelvic Types

Pelvic Evaluation:

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

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.”

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.

PELVIC INLETS:

GYNECOIDPLATYPOIDANTHROPOIDANDROID

  1. Caldwell-Moloy Classification
    1. Gynecoid Pelvis (50%)
      1. Pelvic brim is a transverse ellipse (nearly a circle)
      2. Most favorable for delivery
    2. Android Pelvis (Male type)
      1. Pelvic brim is triangular
      2. Convergent Side Walls (widest posteriorly)
      3. Prominent ischial spines
      4. Narrow subpubic arch
      5. More common in white women
    3. Anthropoid Pelvis
      1. Pelvic brim is an anteroposterior ellipse
        1. Gynecoid pelvis turned 90 degrees
      2. Narrow ischial spines
      3. Much more common in black women
    4. Platypelloid Pelvis (3%)
      1. Pelvic brim is transverse kidney shape
      2. Flattened gynecoid shape

25 thoughts on “Pelvic Types

  1. 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.

    • 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.

  2. In the description of the android pelvis, it states, “The android pelvis ( sometimes called a ‘true make pelvis’ ). Should that be ‘true male pelvis’ ?

  3. 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.

    • 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.

  4. 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.

  5. 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 ?
    Thanks

    • 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.

  6. Thanks. I found the above information and comments very helpful and informative.
    my question:
    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.

  7. 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.

  8. 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.

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