A mother sacrifices her body during pregnancy as it undergoes many changes beneficial for both her and her child. Researchers from Penn State and Northwestern University have examined how a person's body ages who had few births or many tend to have aged quicker than those who gave birth to three or four children.
The researchers noted that these changes could only be seen after the mother had undergone menopause. As the old wives' tale says, having children could add years to a woman.
The study, published in Scientific Reports, suggests that pregnancy and birth may contribute to the changing and dysregulation of many changes in the body that affect the mother after menopause.
"This is consistent with the metabolic, immunological, and endocrinological changes that occur in the body during pregnancy and lactation, as well as the various disease risks that are associated with pregnancy and reproductive investment more generally," says Talia Shirazi, a doctoral candidate in biological anthropology at Penn State.
The cost of reproduction and how it affects aging
The researchers wanted to know how the body balances the "costs of reproduction" and how it affects aging. They said that pregnancy and breastfeeding use a lot of energy that could affect many bodily systems, like blood pressure, immune function, metabolism, and many more.
Also, they said that people who gave birth are more likely to die from kidney disease, diabetes, hypertension, and other conditions than those who have not given birth.
From the evolutionary point of view, this makes sense because the loss of energy in pregnancy and breastfeeding will leave the mother little energy to allocate to her physiological maintenance and defense, the researchers said.
The researchers used the data of over 4,000 participants from the National Health and Nutrition Examination Survey by the Centers for Disease Control & Prevention. the information they gathered includes the number of live births or whether these women have already gone menopause or not.
In measuring the biological aging of the mothers based on their nine biomarkers, they found a U-shaped relationship between the number of live births ad accelerated aging, Futurity reported.
According to the researchers, those who reported zero or few live births, or many, seemed to have quicker biological aging than those who have given birth to three or four live births. Even with controlling the chronological age, lifestyle, and other health-related aging factors, the result of their study still applies.
Is this the effect of lack of ovarian hormones?
Shirazi said that they do not know yet what caused these associations but that it could be due to the lack of ovarian hormones in post-menopausal mothers.
Ovarian hormones protect a woman from cellular level processes that could accelerate aging, Shirazi said. It is possible that ovarian hormones are buffering the potential adverse effects of the "costs of reproduction" on age acceleration in pre-menopausal mothers. Perhaps the lack of hormones after menopause has prompted these adverse effects to show.
But researchers are not certain yet if this is the real cause. They recommend conducting more research regarding the matter to understand the processes involved in aging and having children, and how these processes work in the long run.
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