It is easy to forget that humans are just another species of animals in the world and nature has its answers to everything. We may not notice, but our bodies change in accordance to our biological function. For example, now scientists from the University of Zurich have studied how female pelvis changes through the years and what influences these transformations.
Amazingly, human body prepares itself for new stages in our lives. Female pelvis expands during puberty and then contracts again during menopause, while male pelvis is changing in the same pattern through the years. It is because of the obvious reason – female body has to prepare itself to give birth.
Now scientists found that these transformations are controlled by hormonal changes in puberty and during menopause. For a long time scientists were puzzled why some women have difficulty giving birth because of the shape of their pelvic bones. It was speculated that female pelvis is a result of a compromise – it had to be just wide enough to give birth, but not too wide in order not to interfere with walking. Now, however, scientists think that even if female pelvis was wider it would not prevent women from walking.
Team of scientists used computed tomographic data to track pelvic development from birth to old age. They found that before puberty male and female pelvis does not differ in width much. However, while through puberty male pelvis changes on the same pace and trajectory, female pelvis grows wider, reaching its full width around the age of 25-30 years. Then at around 40 years of age, during the menopause, female pelvis starts to get narrow again.
Scientists found that these transformations are the result of hormone activity in the body. Oestrogen concentration reaches high levels during puberty and remains high until menopause. It allows woman to be fertile and thus maintains pelvic in appropriate form. Interestingly, hormone levels are also influence by environmental factors and nutrition.
Marcia Ponce de León, lead author of the study, said: “This suggests that difficult childbirths are not necessarily an evolutionary mis-step, but more a question of the balance between the hormones and the external factors influencing the size of the birth canal and the prenatal development of the child”.
As possibilities of becoming pregnant decreases, female pelvis contracts, as a narrow pelvis is better suited to stabilizing the pelvic floor. This means that it is makes it a little easier to walk at the older age. Although this research does not provide ground-breaking news, it is an interesting reminder that humans also obey to the plans of nature.