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The epigenetic age and pregnancy.

The epigenetic age and pregnancy.

Image credit: Anastasiia Chepinska/Unsplash

By Jamila on Nov 10, 2020

[1] Michaeli, Tal Falick, Yehudit Bergman, and Yuval Gielchinsky. "Rejuvenating effect of pregnancy on the mother." Fertility and Sterility 103.5 (2015): 1125-1128.

[2] Ziomkiewicz, Anna, et al. "Evidence for the cost of reproduction in humans: high lifetime reproductive effort is associated with greater oxidative stress in post-menopausal women." PloS one 11.1 (2016): e0145753.

[3] Armstrong, Nicola J., et al. "Aging, exceptional longevity and comparisons of the Hannum and Horvath epigenetic clocks." Epigenomics 9.5 (2017): 689-700.

[4] Ryan, Calen P., et al. "Reproduction predicts shorter telomeres and epigenetic age acceleration among young adult women." Scientific reports 8.1 (2018): 1-9.

[5] Kresovich, Jacob K., et al. "Reproduction, DNA methylation and biological age." Human Reproduction 34.10 (2019): 1965-1973

Shubhankar Kulkarni 6 days ago
A recent study reported the changes observed in the epigenetic age between during pregnancy and 1 year postpartum. The average age of the 35 women included in the study was about 33 years. [1]

The results suggested that the epigenetic age decreased from mid-pregnancy to 1 year post-partum,
with respect to PEAA (Phenotypic Epigenetic Age Acceleration), GrimAge (a cumulative score of 12 epigenetic markers), DNAm PAI-1 (plasminogen activator inhibitor-1; a marker or cardiovascular disease), and immune cell population epigenetic age indices (EEAA - extrinsic epigenetic age acceleration, age-adjusted proportion of senescent CD8+ T cells and naïve CD8+ T cells). In non-pregnant adults, EEAA and the age-adjusted proportions of senescent CD8+ T cells increase over time, and the age-adjusted proportion of naïve CD8+ T cells decrease over time. [2, 3, 4] The current study reported that the opposite from pregnancy to the post-partum period. This suggested a regeneration of T cells from pregnancy to the post-partum period, potentially indicating a partial postpartum rejuvenation. Overall, pregnancy may slow some aspects of aging.

Limitations of the study:
1. Small sample size
2. Changes over the full length of the pregnancy (from before being pregnant) were not observed.
3. We do not know whether the women were previously pregnant or not.
4. The observed change in the epigenetic age between mid-pregnancy and 1 year post-partum could
be affected by a decrease in weight in the postpartum period.

References:
1. Ross KM, Carroll J, Horvath S, Hobel CJ, Coussons-Read ME, Dunkel Schetter C. Immune epigenetic age in pregnancy and 1 year after birth: Associations with weight change. Am J Reprod Immunol. 2020 May;83(5):e13229. doi: 10.1111/aji.13229. Epub 2020 Mar 12. PMID: 32061136.
2. Kananen L, Marttila S, Nevalainen T, et al. The trajectory of the blood DNA methylome ageing rate is largely set before adulthood: evidence from two longitudinal studies. Age (Dordr). 2016;38(3):65.
3. Marttila S, Kananen L, Hayrynen S, et al. Ageing-associated changes in the human DNA methylome: genomic locations and effects on gene expression. BMC Genom. 2015;16:179.
4. Pawelec G, Larbi A, Derhovanessian E. Senescence of the human immune system. J Comp Pathol. 2010;142(Suppl 1):S39-S44.
Jamila 2 days ago
Shubhankar Kulkarni the study is very interesting. Thanks for bringing it to my attention. The study would have been even better if they had tested the epigenetic age prior to the pregnancy! Then we could've determined the epigenetic age throughout the different phases. It also would've helped to know more background information about the women like whether this was their first child or not.

Just a silly thought in my head, but what if pregnancy rejuvenates the female depending on their age. For example, in "older" females, the epigenetic age might decrease due to pregnancy, but in "younger" women, the epigenetic age increases/doesn't change as much due to pregnancy. So, the rejuvenating effect might only be seen in the "older" women. ☺️

Shubhankar Kulkarni 2 days ago
Jamila That can be true. There can be a J-shaped curve where the female's epigenetic age might decrease if she is pregnant in an age time window that is optimum for pregnancy. The epigenetic age of females pregnant before and after the time window might see an increase.
Shubhankar Kulkarni 15 days ago
Excellent idea! Epigenetic may help us solve the debate.
1. I would like to add another age group on the left-hand side of the spectrum since the reproductive age starts well before 18 years of age.
2. Different age groups are very much necessary for this research. The age group in which the increase in the epigenetic age with gravidity is the lowest can be, probably, considered as the best age to conceive, at least, biologically.
Jamila 15 days ago
Shubhankar Kulkarnigood idea. We would need to cover the spectrum of ages to get a better sense of how the age at the time of pregnancy impacts the ageing process.

That's also very true. The research has vast implications. Firstly, it would tell us whether the pregnancy is beneficial or detrimental for mothers. Secondly, if there is an age group that has no effect or a little increase in the epigenetic age, then this would be a good age to conceive, as you said.

However, there is also a possibility that certain age groups have a decreased epigenetic age because of pregnancy - this would be fascinating if it does happen.