Why can bones no longer be the same after the birth of a child?

A new study of Macaca monkeys has shown that pregnancy may leave a lasting mark on the skeleton.

After birth, female macaca monkeys show markedly lower concentrations of calcium, phosphorus, and magnesium in their bones compared with those who have not experienced pregnancy, writes Science Alert.

While this particular study did not examine people, the findings help to inform how major events in life can leave a signature in the skeletal tissues of primats in general.

Although they may look like muscle - covered concrete poles, the Primat bones are surprisingly dynamic. Bones grow gradually throughout life, and rising annual changes are often influenced by lifestyle factors.

Most of us know that bone density can be lost over age, especially after menopaus, but during life, disease, diet, climate and pregnancy can leave a permanent record in calcified tissue that can be “lax” in the afterlife.

Evidence suggests that during pregnancy in humans, the mother's body can draw calcium from her bones, where poor nutrients are swallowed, reducing the mass, composition, and density of her skeleton for a time.

As you breastfeed, your mother's bones actually “are resurged” into her blood to produce enough calcium-rich milk. Lost minerals are easily replaced when the curve stops, but even then scientists may notice a short - term shortage.

In legal medicine and archaeology, bone - based pregnancy - especially hip marks from birth - has been considered unreliable, and today the methods and interpretations of this work vary greatly. Maybe it's time to look deeper into the bones in the country.

Our “Hulum indicates that even before the end of fertility, the skeleton dynamically responds to changes in reproductive status”, says anthropologist Paola Cerrito of New York University.

These findings confirm once again the significant impact of childbearing on the female organism, simply, the evidence of reproduction “is written on bone” throughout life.

The study is based on only seven naturally dying macaw monkeys, four of whom were females, but among this limited group, femurs showed relative differences that could be explained only by pregnancy and lactation.

Two female monkeys who were reproduced throughout their lives showed relatively different bone compounds, including lower calcium, phosphorus, and magnesium content. The changes noted in the density of calcium and phosphate were accompanied by birth, while the decline in magnesium content coincided with lactation.

The authors suspect that their findings are a sign of bone resurgeon in reproduction, but further studies are needed to determine this with certainty.

“The findings related to basic reproduction changes are important because birth detection from mineralised tissue is still a largely unexplored area of research with important implications for evolutionary, conservative and archaeological studies,” writes the authors.

More research is needed, possibly using representatives of wildlife populations to see if the same can be said of other animals.