Pregnancy, while a profound and transformative experience, bears more than just the physical changes associated with childbirth. Recent research suggests that the process of gestation leads to alterations in the distribution of specific chemical markers on a pregnant individual’s DNA, resembling changes typically associated with aging. However, a groundbreaking study indicates that several months after giving birth, these chemical patterns revert to a state reminiscent of earlier stages. The findings, published on March 22 in Cell Metabolism, bolster previous studies conducted on mice and preliminary investigations in humans.
Perinatal-health specialist Kieran O’Donnell, hailing from Yale University, describes the reversal as “somewhat unexpected,” underscoring the surprising resilience of biological age following pregnancy.
The study scrutinized chemical tags known as methyl groups, which are appended to DNA through a process called methylation. These methyl groups constitute a facet of the epigenome, orchestrating changes in gene activity without modifying the genetic code itself. Researchers have harnessed DNA methylation patterns to estimate a person’s ‘biological age,’ reflecting the physiological stresses accrued over time. Unlike chronological age, biological age is malleable, fluctuating in response to various factors.
Biomedical scientist Vadim Gladyshev, part of the team from Harvard Medical School, underscores the fluid nature of biological age, emphasizing its susceptibility to alteration. The team’s prior research on mice hinted at a decline in biological age post-pregnancy, hinting at a potential parallel in humans.
The latest study not only corroborated previous findings in humans but also unveiled variations in postpartum biological age recovery. Individuals on the brink of obesity before pregnancy exhibited a lesser reduction in biological age three months after birth compared to those with a ‘normal’ body weight. Additionally, exclusive breastfeeding correlated with a more pronounced decrease in biological age compared to formula feeding or a combination of both.
Although some participants showcased biological ages younger postpartum than during early pregnancy, researchers refrain from attributing this phenomenon definitively to rejuvenation effects. Instead, they advocate for further longitudinal studies to elucidate the underlying mechanisms.
Interpreting these findings presents challenges, as methylation dynamics during pregnancy may not necessarily denote accelerated aging. Physician-scientist Dena Dubal of the University of California, San Francisco, posits that methylation could underlie the significant physiological shifts necessitated by pregnancy, rather than strictly signify aging.
Amidst the nuances of interpretation, scientists urge against undue concern regarding pregnancy-induced alterations in biological age. Gladyshev reassures that such changes are modest, typically spanning only two to three years. Moreover, Dubal emphasizes that pregnancy, while a transformative journey, should not be viewed solely through the lens of biological aging, emphasizing the multitude of factors contributing to maternal and fetal well-being.
