The study suggests that pregnant women may speed up biological aging

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While chronological age simply reflects how long someone’s been alive, biological age reflects their physiological state and chances of age-related diseases and death.
The pattern still showed up when the scientists controlled for other factors that also affect a person’s rate of biological aging, such as socioeconomic status, smoking history and some genetic risk factors.
This pattern of biological aging in men is consistently seen across epigenetic-clock studies and may be connected to men generally dying at younger ages than women, Ryan said.)
Based on all of these data, the team estimates that each pregnancy was tied to about 4 to 4.5 months of biological aging among the women in the study.
Similar upticks in biological aging have been seen in some other contexts, but not all.
So “we do have decent evidence of biological aging being sped up from pregnancy, but maybe not in all contexts,” Ryan said.
For now, this new study is helping scientists start to unpack the impact of pregnancy on the aging process.
If they can identify factors that help buffer against biological aging, scientists could potentially design interventions that mimic those factors in people more susceptible to it.


A recent study indicates that women in their early 20s who have become pregnant are “biologically older” than those who have never become pregnant, and that this age difference appears to increase in those who have become pregnant more than once.

The study, carried out in the Philippines, examined people’s epigenetics—the chemical labels affixed to their DNA—using a variety of instruments. These tags aid in regulating which genes are activated and to what extent, without altering the underlying code of the DNA. The new study focused on methyl groups, a class of molecules that has been historically associated with various aspects of the aging process.

Scientists have developed a number of “epigenetic clocks” that can be used to determine an individual’s biological age by examining patterns of methylation observed throughout the human life span. While biological age represents a person’s physiological state and likelihood of age-related diseases and death, chronological age only indicates a person’s length of life.

Calen Ryan, an associate research scientist at the Columbia Aging Center and first study author, explained that “what epigenetic clocks are doing is they’re serving a predictive function rather than a sort of causal explanation.”. They are trained to anticipate events that we interpret as signifying different facets of aging. Thus, a person’s chronological age may be predicted by one clock, their chance of dying by another, and their telomere length—the protective caps at the end of DNA that prevent it from fraying—by still another.

Related: “Biological aging” accelerates during periods of extreme stress, but it can also be reversed during the healing process.

The study made predictions about 1,735 young men and women in the Philippines using six distinct epigenetic clocks, and it was published on Monday, April 8, in the journal PNAS. Blood samples from all members of the group, ages 20 to 22, were collected in 2005. About 330 of the women who fell pregnant in the years after their initial blood sample had a follow-up sample taken four to nine years later.

The analysis showed that women with at least one pregnancy, including those that ended in miscarriages, stillbirths, and live births, aged more quickly than women without any prior pregnancy history across all of the clocks used. Even after the researchers took into account additional variables like socioeconomic status, smoking history, and certain genetic risk factors that can also influence an individual’s rate of biological aging, the pattern persisted.

According to Ryan of Live Science, the researchers also discovered that women with a higher number of pregnancies aged more quickly than those with a lower number of pregnancies “for all six of the clocks.”. “Among the men we examined cross-sectionally, we do not find that relationship. Put another way, a man’s epigenetic clock seemed to run at the same pace regardless of how many children he fathered.

(It should be noted that, regardless of whether or not they were pregnant, the men generally appeared biologically older than the women; the men’s biological ages were simply not raised by pregnancy. According to Ryan, there may be a connection between men’s consistent biological aging pattern and the fact that they typically die younger than women in epigenetic clock studies. ).

The researchers then examined the 330 women they had been tracking over time to look for any variations between the blood samples from the first and second visits. According to that analysis, having more pregnancies was linked to aging more quickly than having fewer pregnancies. Only two of the six clocks, namely the two intended to estimate chronological age, displayed this pattern, though.

The researchers calculate that each pregnancy was associated with roughly 4 to 4.5 months of biological aging in the study’s participant women based on all of these data.

Related: Mammal life span maximums and epigenetics are related.

The location of the study may have had an impact on its conclusions. Inequality in the Philippines, for example, may affect how much aging is influenced by pregnancy depending on a person’s ability to obtain appropriate nutrition, medical care, and social support during pregnancy. It’s also noteworthy that the majority of epigenetic clocks have been shown to be accurate in predicting aging in white individuals living in developed nations; however, many clocks still require extensive validation in individuals belonging to other demographic groups worldwide, as Ryan pointed out.

Though he acknowledged that they might be enhanced for various populations, he said, “they’re still basically our best measures yet.”. As the authors pointed out in their report, more research is required to separate the effects of parenting on aging from those associated with getting pregnant and providing birth.

Furthermore, Ryan noted of the study participants, “these women are quite young at the time of the sample.”. Therefore, it’s unclear whether older women would exhibit the same patterns during their first pregnancy. That being said, the team’s focus on young women was advantageous because they aimed to determine whether biological aging associated with pregnancy could be detected early on, before the negative effects of accelerated aging manifest.

Ryan stated that if this accelerated aging can be identified early on, it may help guide future treatments that aim to slow down or stop the process. However, at this early stage of research, it’s unclear exactly what these treatments would involve.

Some other contexts have not shown an increase in biological aging comparable to this one. For instance, they have been noted in Filipino women residing in the U. S. however, not in Finnish women. Epigenetic clocks speed up during pregnancy, but they mostly stop after the baby is born, especially in breastfeed mothers, according to a recent Yale study.

Accordingly, “we do have decent evidence that biological aging is sped up from pregnancy, though maybe not in all situations,” according to Ryan.

For the time being, this new study is assisting researchers in beginning to explore how pregnancy affects aging. However, it might eventually open the door for medical advancements.

In other words, people who might age more with each pregnancy, Ryan expressed his hope that “we can start to maybe use tools like this [epigenetic clocks] to identify at-risk individuals.”. It is possible for scientists to create interventions that mimic factors that help prevent biological aging in individuals who are more vulnerable to it if they can identify those factors.

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