Pregnancy isn't all about the pain. It can lead to changes in the distribution of certain chemical marks in a mother's DNA, resembling signs of aging. However, recent research suggests that within a few months after childbirth, the distribution of these chemical marks reverts back to an earlier state. The related paper was published on March 22nd in Cell Metabolism.
Giving birth can reset someone's DNA markers to a younger state, but this trend is less pronounced in newborns with obese parents. The image source is from Chicago Tribune/Getty.
"This reversal is somewhat unexpected," said Kieran O'Donnell, a perinatal health expert at Yale University and co-author of the paper.
The chemical markers analyzed in the study are called methylation, which are added to DNA through a process called methylation. DNA methylation patterns can be used to assess a person's "biological age," reflecting the physiological stress accumulated by the body over time. Some studies have found that biological age is more predictive of health issues such as cardiovascular disease and dementia than chronological age.
"But unlike chronological age, biological age is very flexible, a fluid parameter that can fluctuate up and down," said Vadim Gladyshev, a biomedical scientist at Harvard Medical School in the United States. Last year, his team published a study in Cell Metabolism showing that the biological age of mice decreases after pregnancy, indicating that humans may also have similar effects.
O'Donnell and colleagues found that individuals on the cusp of obesity before pregnancy did not experience a significant decrease in biological age compared to those with normal weight within three months after childbirth. However, those exclusively breastfeeding experienced a greater decrease in biological age compared to those using formula or a combination of formula and breastfeeding.
"Some participants had a biological age several years younger after childbirth, which caught my attention," said Yousin Suh, an aging biologist at Columbia University in the United States, who was not involved in the work.
O'Donnell said the researchers did not assess participants' biological age before pregnancy, so "we cannot claim this is a rejuvenation effect." However, these data are inspiring, and he hopes to continue investigating participants in the future.
Methylation undergoes significant changes during pregnancy, but "we believe it is a mistake to consider pregnancy as a state of accelerated aging," said Dena Dubal, a medical scientist and aging expert at the University of California, San Francisco. She thinks methylation may not be a marker of aging, but rather some changes the body undergoes to support fetal growth, such as changes in gene expression.
However, Suh is not certain about this. "So far, methylation is one of the most powerful markers of biological age." O'Donnell, on the other hand, says whether reversible states can truly be called "age" is a very important question.
Scientists say people should not worry about the increase in biological age associated with pregnancy. Dubal pointed out that pregnancy should not be defined as a biological problem, even for those who cannot breastfeed and therefore maximize their biological age. "While breastfeeding has many benefits, not breastfeeding is not a perilous situation."
Related paper information: https://doi.org/10.1016/j.cmet.2024.02.016
