Scientists Discover New Permanent Changes Caused by Giving Birth

Pregnant Giving Birth

The researchers discovered that females who had given birth had lower levels of calcium, magnesium, and phosphorus.

A study of primates reveals permanent changes in bone composition after birth and breastfeeding.

Reproduction permanently alters females’ bones in ways not previously known, a team of anthropologists has found. Its discovery, based on an analysis of a kind of primate known as rhesus monkeys, sheds new light on how giving birth can permanently change the body.

A group of anthropologists has discovered that reproduction permanently changes women’s bones in ways that were not previously known. The discovery, based on an analysis of rhesus monkeys, gives new insight into how birth can permanently alter the 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,” explains Paola Cerrito, who led the research as a doctoral student in New York University’s Department of Anthropology and College of Dentistry.

The scientists discovered that females who gave birth had lower calcium, magnesium, and phosphorus concentrations. These changes are connected to giving birth itself and to lactation.

They do, however, issue a warning that although prior clinical studies have shown the importance of calcium and phosphorus for healthy bones, the current findings address overall health implications for either primates or humans.  Rather, they assert that the study reveals the dynamic nature of our bones.

Primate Femora

Microscope images of the cross-section of the seven femora (thigh bones) included in this study, identified by age and sex. Credit: Paola Cerrito and Timothy Bromage

“A bone is not a static and dead portion of the skeleton,” notes NYU anthropologist Shara Bailey, one of the study’s authors. “It continuously adjusts and responds to physiological processes.”

Timothy Bromage, a professor at NYU College of Dentistry, Bin Hu, an adjunct professor also at NYU, Justin Goldstein, a Ph.D. student at Texas State University, and Rachel Kalisher, a doctoral student at Brown University, are the other authors of the study, which was published in the journal PLOS ONE.

It’s been long-established that menopause can have an effect on females’ bones. Less clear is how preceding life-cycle events, such as reproduction, can influence skeletal composition. To address this, the researchers studied the primary lamellar bone—the main type of bone in a mature skeleton. This aspect of the skeleton is an ideal part of the body to examine because it changes over time and leaves biological markers of these changes, allowing scientists to monitor alterations during the lifespan.

In the PLOS ONE study, the scientists examined the growth rate of lamellar bone in the femora, or thigh bones, of both female and male primates who had lived at the Sabana Seca Field Station in Puerto Rico and died of natural causes. Veterinarians at the field station monitored and recorded information on these primates’ health and reproductive history, allowing the researchers to match bone-composition changes to life events with notable precision.

Cerrito and her colleagues used electron microscopy and energy-dispersive X-ray analysis—commonly deployed methods to gauge the chemical composition of tissue samples—to calculate changes in concentrations of calcium, phosphorus, oxygen, magnesium, and sodium in the primates’ bones.

Their results showed different concentrations of some of these elements in females who gave birth compared to males as well as females who did not give birth. Specifically, in females who gave birth, calcium and phosphorus were lower in the bone formed during reproductive events. Futhermore, there was a significant decline in magnesium concentration during these primates’ breastfeeding of infants.

“Our research shows that even before the cessation of fertility the skeleton responds dynamically to changes in reproductive status,” says Cerrito, now a research fellow at ETH Zurich. “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.”

Reference: “Elemental composition of primary lamellar bone differs between parous and nulliparous rhesus macaque females” by Paola Cerrito, Bin Hu, Justin Z. Goldstein, Rachel Kalisher, Shara E. Bailey and Timothy G. Bromage, 1 November 2022, PLOS ONE.
DOI: 10.1371/journal.pone.0276866

The study was funded by the National Science Foundation and the National Institutes of Health (NIH). 

23 Comments on "Scientists Discover New Permanent Changes Caused by Giving Birth"

  1. Charles G. Shaver | December 7, 2022 at 5:24 am | Reply

    So, how well does that correlate with human females who have access to nutritional supplements during pregnancy and breast feeding?

  2. They do know animals aren’t the best for testing in right. I mean mice and rats get foods tested in them as they react most like humans do… Yet you’d be surprised to know the chances of food related health issues that the animal testing says shouldn’t do much if say one guy tests processed food… Would be wrong as someone did and in less than a month they developed many health issues directly linked to the foods in animal studies. As the animals can also eat uncooked meat and dead rotting things and live in conditions that would kill us or make us sick…

    • That’s 19th century animal testing, we generally know which animals systems react similarly to our own and take steps to mitigate issues where a mismatch could occur. They don’t test with such poor and outdated techniques as you infer. Pharma and additives mostly, food testing is largely done on humans.

      You can test bone density in a primate with a lifespan of maybe 15 years in the wild (30-almost 40 in captivity) in much less time than it takes to wait 60-90 years to test a humans bone density. You’d have to wait another 30 years before you could get any usable human data from pregnancy and the large dose supplements we’ve only really been feeding women over the last 50 years.

  3. While I agree there’s a lot of factors I feel like this does open a door into the research of not just bones but women in health and science as I don’t feel there have been enough proper studies done

  4. Alchemist Angela | December 8, 2022 at 11:42 am | Reply

    If human evolution were as it’s incorrectly told this would hold weight indeed. We did NOT evolve from monkeys,however.

    • No we didn’t evolve from monkeys, but monkeys share a common ancestor to ourselves and have evolved as much as we have in that time, albeit in a very different direction.
      If you have religious objections, tell them to your pastor.
      There’s a huge difference between truth and belief.

  5. As a non professional who both gave birth and nursed for 16 months, my son had projectile vomiting that I would have to eat more to create more milk to make up for loss and still came away borderline anorexic per my pediatrician notes pre-pregnancy, more so with nursing. I had difficulties due to this and to gain weight at all as a tobacco smoker which I managed to reduce slightly not quit. I also had extreme stressful events with a restraining order against my son’s father leaving a gray streak in my hair while pregnant. Within 10 years from birth, my acupuncturist and biodermal screener also determined the flap from SM to LG intestine was blocked and other symptoms that I was treated for dead calcified tapeworm cysts which my cat had nearly 10vyears earlier. My IBS – D took years and many diet and environmental changes necessitating a post disability period to recover to restore balance between these experiences adding in my home and work high irritant level environments. After quitting hormone based contraceptives at 34, I had both quit smoking and my child and I became long term largely plant based from child’s age 9 and on, before I went vegan- which began giving me further issues in 40’s decade of perimenopause including weak dental enamel, gum and ligament loss. I then quit vegan and began eating chicken and beef that I’d abstained of while I’d kept fish, eggs, raw cheese up to going macrobiotic for 2 years dropping to only while meat fish before going vegan for 15 month’s which caused significant weight decline and body temperature loss alongside heightened IBS – D. There is definitely more to this than only birth and nursing for human females.

  6. This isn’t new most women who have given birth know this and many other things in our bodies that change,so glad science is finally catching up.

  7. They only studied monkeys so far. Human studies with and without supplements are needed to verify applicability to humans and to answer your question, Charles.

    • Charles G. Shaver | December 9, 2022 at 4:29 am | Reply

      Actually, Holly Hope, I already know the answer. Multiple epidemics of chronic diseases, osteoporosis, failed joints and premature tooth loss are some of the evidence of the US FDA experimenting on humans with soy processed with toxic hexane since the early 1970s (US female breast cancer by 1979), added ‘cultured-free’ MSG since 1980 (US obesity/diabetes by 1990) and others since which tend to aggravate still medically unrecognized chronic subclinical non-IgE-mediated (e.g., so-called “delayed onset”) food and food additive allergies with motherhood and breast feeding exacerbated (in humans, not mice). In the absence of adequate dietary supplies the body denies and/or robs the bones, nerves and teeth of calcium to try to maintain the blood at an optimal pH (slightly alkaline) with estrogen being protective against a high uric acid level in younger women, leaving post menopausal women not on hormone therapy more at risk.

  8. How old is this scientist
    That women in the Human speices have known this for hundreds of years if your not communicating with females in your life you can’t make an accurate analisis. I’m female and now 60 and my Mother and Grandmother told me when I was coming of age at 12. There are alot more changes that are Permanate.once you have a Child.intellect instinct physical hormonal your hole body changes not just your bone structure all females nomatter what species they all go throgh this sqarels mice Fish elphants that’s what makes you a FEMALE going through this . It takes the whole Female Body to produce a Child. This is as Bad as Elon Musk wanting to build his own male Uterise.

  9. Maybe documenting the impact of pregnancy on the nutrient levels in bones in animals is a NEW DISCOVERY, but not the impact of pregnancy on hyman women … ALL of these changes have been known to happen in women for decades. I am 60 and my mother was prescribed nutritional suppliments while she was pregnant with me and my 4 older siblings as well!

    I would like to see research results in changes in a woman’s brain before and after becoming a mom for the first time. I know the impact on me was profound.

    Thats why I read the article, thd brain is part of the body afterall.

    I guess in a hundred years, someone will publish results from research on changes in some otber species before and after birth and suddenly the impact on a females bones due to pregnancy and lactation will be a new discovery all over again.

    • Hi Mom! I noticed you mentioned that you had hoped to find info re: brain changes during pregnancy in this article bc you haven’t seen any research concerning that & in your experience, you had profound cognitive & behavioral changes during/after your pregnancy compared to prior 2pregnancy.

      It just so happens that I randomly came across a recent research article much much earlier today re: this very topic! &Using MRI brain scans to measure amts of grey & white matter, total volume, size of specific areas, etc. One of the major findings was the sig.loss of grey matter in the 1st time pregnancy group during period from pre- to post-pregnancy – this effect wasn’t observed at all in the nonpregnant group. There was another big finding, but I’m blanking atm on which brain areas were involved, sorry! But I do also recall that HIGHER LVLS of grey matter loss was associated with increased bonding, initially with the fetus & later, the infant…&women were more likely to report conceptualizing the fetus as a distinctly separate individual/entity from themselves, whereas w/ lower lvls of grey matter volume loss, women were more likely to conceptualize the fetus as a part or extension of their own bodies. Anyway, just wanted to share that w you! If you go to Google or Google scholar & search for something like “human females MRI grey matter loss brain changes pregnancy”, I’m fairly certain that it should pop up in the results! =) If you search & can’t find it though, just reply to this message of mine, &ill go back thru my internet history to find the link for you. Hope this helps! -Jen

    • *Effect*, not “impact”; pregnancy isn’t crashing into nutrient levels in animal bones. Even in the jargon sense of “strong/violent/marked effect”, saying “I know the impact on me was profound” is redundant. I don’t know where people are learning this nonsense from, but please stop using it.

  10. I agree with Selma – this honestly shouldn’t be news to the scientific community. I am currently nursing my fourth child. I have recently had an x-ray for chiropractic services, and there was a notable loss of bone density there. He recommended that I take a calcium and magnesium supplement to support my bone health.

    • Charles G. Shaver | December 9, 2022 at 4:42 am | Reply

      Be careful what calcium supplement you take, Amarette, because calcium carbonate (minimally) is known to bind with phosphorus causing it to be excreted. Discovered on my own at home in mid-March of 2021 (not tested by healthcare providers for nine years while avoiding a lot of dairy and real meats for allergy reasons) I’m still trying to recover from a serious case of cheaply and easily prevented hypophosphatemia. Some healthcare providers simply ‘assume’ we get enough phosphorus in our diets so demand to be tested for phosphorus (and uric acid; see above).

  11. One more profound finding, some years ago noted the remnant of stem cells from the pregnancy lasting a woman’s lifetime. I was hoping to find some reference here.

  12. I experienced what they are saying .. I figured it out what is explained here by suffering such condition .. My 2nd child is born with hypocalsimia caused by hypoparathyroied .. primarily she had magnesium deficiency as well .. and I could clearly connect with the facts here coz of my deficiency of vitamin D and calcium which I found myself later on suspecting on my own which resulted in my daughters health condition.. In my childhood I always used to suffer leg aching whenever I walked little more or ran never found out or treated my problem they gave iron instead ..caring my child and observing my physical changes I am certain what they found is fact in my case .I definitely believe if I would have taken calcium enrich food and suppliment and had sufficient exposure to sun my daughter wouldn’t have her health issue.

    I will strongly advise parents and specially all women to understand your body and it’s need and take care of yourelf on your won.

  13. As the previous comment said how old is the researchers, women have known this for centuries, but no one asked.So now what.

  14. What about women that have O-( no rhesus gene) blood? Is there any info on what that does to a women’s body? T.I.A.

  15. Is there any relation to the hip surgery? What’s the ratio on male -female deteriorating aged hips?

  16. I nursed my son for eleven mounts and my daughter for four years. Does this mean I will have osteoporosis?

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