Pregnancy may speed up biological ageing, study suggests
The study involving 825 young women, all born in the same year, found that each individual pregnancy a woman reported was linked with an additional two to three months of biological ageing
Research suggests pregnancy can accelerate biological age in women.
Two new studies analyzing genetic markers in pregnant women's blood cells indicate an accelerated ageing process, potentially adding additional months or even years to their biological age throughout pregnancy, reports The Washington Post.
But one of the studies also suggests this process may reverse itself once a woman gives birth, rewinding time so that some mothers' cells seemingly end up biologically younger afterward than they'd been during gestation, especially if a mother breastfeeds her baby.
Together, the studies underscore how physically demanding pregnancy is. But they also raise important questions about ageing itself and whether it can really be sped up, slowed, or reversed by pregnancy.
Keep updated, follow The Business Standard's Google news channel
The newest of the studies, published today in Proceedings of the National Academy of Sciences, found pregnancy "has a big impact on a woman's body" and biological age, said Calen P Ryan, an associate research scientist at the Columbia ageing Center at Columbia University in New York, who led the new research.
In it, scientists looked at the reproductive histories and DNA samples from 1,735 people in a long-term, continuing health survey in the Philippines to investigate the influence pregnancy has on the ageing process.
They calculated participants' biological age using six different "epigenetic clocks"—genetic tools that estimate biological age based on patterns of a process called DNA methylation.
The study involving 825 young women, all born in the same year, found that each individual pregnancy a woman reported was linked with an additional two to three months of biological ageing, and women who reported being pregnant more often during a six-year follow-up period showed a greater increase in biological ageing during that period.
The relationships between pregnancy and biological ageing persisted even when the authors accounted for socioeconomic status, smoking, genetic variation and the built environment in participants' surroundings.
According to The Guardian, the authors failed to find a link between increased biological ageing and the number of pregnancies fathered by 910 same-aged men from the same health survey.
Calen Ryan told The Washington Post, "Our findings suggest that pregnancy speeds up biological ageing, and that these effects are apparent in young, high-fertility women. Our results are also the first to follow the same women through time, linking changes in each woman's pregnancy number to changes in her biological age."
"Many of the reported pregnancies in our baseline measure occurred during late adolescence when women are still growing. We expect this kind of pregnancy to be particularly challenging for a growing mother, especially if her access to healthcare, resources or other forms of support is limited," he explained.
"We still have a lot to learn about the role of pregnancy and other aspects of reproduction in the ageing process. We also do not know the extent to which accelerated epigenetic ageing in these particular individuals will manifest as poor health or mortality decades later in life," he further added
Similarly, the other new study, published in March in Cell Metabolism, used several different epigenetic clocks to estimate the changing internal age of pregnant women at several points during their pregnancies.
"We were very interested in looking at the impacts of pregnancy as a naturally occurring stress test," said Kieran J O'Donnell, an assistant professor at the Yale Child Study Center and Yale School of Medicine, who oversaw one of the new studies.
With blood samples from 119 pregnant American women and five different clocks, the researchers tracked the epigenetic changes related to the women's biological age, starting early in gestation and ending three months after they'd given birth.
The clocks again agreed that pregnancy seemed to be ageing the incipient moms as they approached full term, making their blood cells' DNA appear to be as much as two years older than it had been earlier in the pregnancy.
More encourageing, though, O'Donnell said, is that this ageing seemed to reverse for most of the women within three months after birth. In general, their patterns of DNA markers soon reverted to an earlier, more-youthful state, and for some new moms who'd breastfed exclusively in the first three months postpartum, overshot the mark, leaving them apparently "younger" biologically than before, by as much as eight years, the study's authors wrote, "indicating a pronounced reversal of biological ageing."
