Reproduction changes women’s bones forever

A new study by a team of anthropologists at New York University has found that reproduction permanently changes a woman's skeleton.

Maria Zavialova

The super skill called “reproduction” affects the female bones in ways unknown before. In a new study published in the journal PLOS ONE*, American scientists have found new evidence of how the ability to have children changes a woman’s body.

Our findings provide additional evidence of the profound impact that reproduction has on the female organism, further demonstrating that the skeleton is not a static organ, but a dynamic one that changes with life events.

Paola Cerrito, who led the research as a doctoral student in NYU’s Department of Anthropology and College of Dentistry, for News Medical.

The research is based on the analysis of primates. Anthropologists have found that the concentration of calcium, magnesium and phosphorus is lower in women who have given birth to children. These changes are associated with childbirth and lactation.

Of course, previous clinical studies have shown that calcium and phosphorus are essential for optimal bone strength. However, the researchers note that the new findings do not apply to the overall health consequences for primates and humans. Rather, they say, the work highlights the dynamic nature of our bones, and how it is affected by reproduction.

Bone is not a static and dead part of the skeleton. It is constantly adapting and responding to physiological processes.

Shara Bailey, study author and anthropologist, New York University


As it was established earlier, menopause can affect women’s bones. To find out how previous life events, particularly reproductive function, affect skeletal composition, the researchers studied primary lamellar bone. This is the main type of bone in the mature skeleton. It is an ideal body part to study since it changes over time and leaves biological markers of these changes. This allows scientists to follow them throughout life.

Anthropologists studied the growth rate of the femoral lamina in male and female primates that lived at the Sabana Seca Field Station in Puerto Rico and died of natural causes. Veterinarians at the field station monitored and recorded information about the health and reproductive history of these primates, which allowed the researchers to compare changes in bone composition with life events with precise accuracy.


The results showed differences in calcium, phosphorus, oxygen, magnesium and sodium concentrations in females who had given birth compared to males, as well as females who had not given birth. In particular, females who gave birth had lower levels of calcium and phosphorus in bones formed during pregnancy. In addition, there was a significant decrease in magnesium concentration when these primates breastfed their infants.

Our research shows that even before the cessation of fertility, the skeleton responds dynamically to changes in reproductive status. Moreover, these findings reaffirm the significant impact giving birth has on a female organism, quite simply, evidence of reproduction is ‘written in the bones’ for life.

Paola Cerrito

*PLOS ONE is an international, interdisciplinary, peer-reviewed scientific journal that publishes research and reviews in the natural and medical sciences. It was founded in 2006 by the non-profit organization Public Library of Science.

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