Enlarge image

Pregnant women (symbolic image)

Photo: Getty Images

Pregnancy increases a woman's biological age, at least temporarily. This is suggested by an analysis by the US Yale School of Medicine, which is reported in the journal “Cell Metabolism”.

According to the paper, in the 20 weeks between early and late pregnancy, a mother ages by two years - biologically speaking. However, the research group concluded that this aging is not permanent: a few months after birth, the effect appears to reverse significantly - and in some cases to a surprising extent.

A woman's body changes extensively during pregnancy: the growing fetus shifts the organs in her abdomen, pelvic joints become looser, and pregnancy hormones change appetite and energy levels. Even the neurons in the brain sometimes permanently rewire themselves.

Biological age measured in the genome

Last year, a research group at Harvard Medical School in the US described that the stress of pregnancy can increase a woman's biological age by up to two years. A team led by perinatal researcher Kieran O'Donnell and biostatistician Hung Pham from the Yale School of Medicine now examined the phenomenon in a similar study with a larger group of test subjects - and came to a similar result.

Biological age can differ significantly from chronological age, which corresponds to the actual years of life: it is determined by genes as well as external influences, which also include lifestyle. It is measured using so-called DNA methylation. These are tiny chemical modifications of the genetic material that – unlike DNA itself – can change over the course of a lifetime. These methylations form certain patterns that researchers can use to estimate a person's biological age.

For the current study, the scientists analyzed blood samples from 119 women at various times during and after pregnancy. They found that the stress of pregnancy accelerates aging, as work by Harvard Medical School had previously shown. Similar effects are known from unhealthy food, alcohol, nicotine or stress.

And after birth: rejuvenation

O'Donnell and his team were surprised when they determined the biological age of the women a few weeks after birth. "Three months after birth, we found a remarkable decline in biological age, in some people even by eight years," O'Donnell is quoted as saying in a statement. While pregnancy increases biological age, there is a clear and pronounced recovery in the period after birth, says the scientist.

A high body mass index in the mother before pregnancy has a negative impact on this recovery effect, according to another result of the study. In other words, women who were overweight before giving birth did not recover as significantly in biological age after giving birth. In contrast, breastfeeding resulted in a greater decline in maternal biological age within three months of birth.

According to O'Donnell, these observations offer interesting new impulses for aging research - although there are a few things to keep in mind: It is not clear whether the recovery effect after birth is relevant for the short- or long-term health outcomes of mothers, and whether these effects extend over time accumulated over several consecutive pregnancies.

O'Donnell cites a second unknown: "Similarly, we do not know whether the reduction in biological age after birth is simply due to the system recovering to the biological age before pregnancy, or, more provocatively, whether pregnancy has a rejuvenating effect.«

ahh/dpa