Pregnancy is linked to faster epigenetic aging in young women

I think the flaw in this study (from what I can see) is that they are looking at pregnancy but measuring differences only post-child rearing.

It has been reported that reduced sleep due to child rearing accelerates epigenetic aging (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10027398/) which looks at the amount of sleep.

This doesn't mean the pregnancy study is wrong. However, we'd need to look at the epigenetic clock pre-pregnancy, at labour, and post-child rearing to understand at what point in the cycle the aging biomarkers are shifting.

We understand they shift post-pregnancy, I don't believe this study shows them to shift pre-labour.

effect of having been pregnant was equivalent to between 4.0 and 14.2 mo of accelerated aging for first- and second-generation clocks, an accelerated pace of aging of 3.3% per year according to DunedinPACE, and a shortening of 0.03 kilobases according to DNAmTL.

This is basically junk science. If you dig into the research on "epigenetic clock measures of biological aging" you'll find very little evidence that things which change those measures actually impact human lifespans. The reality is that there are still no reliable biomarkers for aging.