By Cathy Daub, PT CD, CCE (BWI)
by Cathy Daub
Did you know that all people are about the same size from their neck to their groin? You can know that this is true because when we sit around the table together, we are looking about the same size. This is because what makes us taller or shorter is the growth of the epiphseal plates in the bones of our legs. Therefore being short means you have just as much room to grow and birth a baby as someone who is taller.
Imagine a pregnant woman being told that her pelvis is small and that she has a big baby. It is essential that she knows her pelvis has plenty of room to birth her baby and that nobody can accurately predict the size of a baby until he/she is born. The only exceptions may be malformed pelvic bones perhaps due to an accident, polio, or genetic malformations or the presence of large fibroids.
It is essential that she understands the TRUTH about her pelvis early in pregnancy so that if such things are said to her (nocebo effect – what is said causes harm), she does not allow them to take weight in her psyche. In BirthWorks childbirth preparation classes, women are encouraged to say the affirmation, “My pelvis has plenty of room” and repeat it over and over again. This is the reason why birthing parents are encouraged to take BirthWorks classes as early in pregnancy as possible, or even before pregnant.
Comparisons of Male and Female Pelvis
The male pelvis and female pelvis are not designed in the same way. You can see from the following comparisons that the female pelvis is designed to birth a baby and the male pelvis is not.
- Larger and broader with iliac crests flaring outward
- Overall design is wider.
- Women have wider hips and therefore a greater subpubic angle of 50-60 degrees
- Sacrum is shorter, wider, and more curved posteriorly and has a less pronounced promontory
- Pelvic outlet is slightly oval and rounded (more room)
- The greater sciatic notch is wider
- The ischial spines (sit bones) and tuberosities (projections) are lighter and project less into the pelvic cavity as compared to the male pelvis.
- Taller and higher with iliac crests more upward
- Overall design is more compact.
- Hips are more narrow with a smaller subpubic angle of 70-90 degrees.
- Sacrum is long, narrow, more straight and has a pronounced sacral promontory.
- Pelvic outlet is heart shaped
- The greater sciatic notch is more narrow.
- The ischial spines (sit bones) and tuberosities (projections) are heavier and project farther into the pelvic