Abstract
Pregnancy and aging are associated with stress on the body and show multi-system physiological changes. We asked whether we can learn about aging from the changes in pregnancy. To do so, we analyzed weekly cross-sectional data on 70 lab tests from 300,000 pregnancies and 1.4 million non-pregnant females aged 20–89. Using a biological age model trained on non-pregnant females, we observed that pregnant females’ apparent age dropped by 5 years in the first trimester, rose by 20 years toward delivery, and recovered postpartum. Pregnancy complications increased apparent age by 2–6 years. Certain systems exhibited apparent rejuvenation – opposite trends in pregnancy vs aging – including renal, iron, and most liver tests. Others, such as coagulation, thyroid, muscle, and metabolism, showed apparent aging. Notably, the aging-like mechanisms of pregnancy differed from normal aging, suggesting superficial similarity, whereas the rejuvenation-like mechanisms may offer clues for slowing aspects of biological aging.
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Data availability
The Clalit data used in this study are available on the GitHub page: https://github.com/AlonLabWIS/PregAging. They have also been deposited in the Dryad database: https://datadryad.org/dataset/doi:10.5061/dryad.1c59zw44t. The LabNorm reference Clalit population26 is available at https://tanaylab.weizmann.ac.il/labs/. The raw Clalit data are protected and are not available due to data privacy laws. The original NHANES data are fully available from their website29. All processed data are available at the GitHub page.
Code availability
The source code used to perform the analysis is available from the GitHub page. The repository is open for public use: https://github.com/AlonLabWIS/PregAging.
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Acknowledgements
We thank all members of our lab and Ido Solt, Amos Tanay, and Neta Mendelsohn for discussions. We thank Gabi Barabash and Ran Balicer for the Clalit−Weizmann collaboration. Data acquisition was approved by the Clalit Helsinki Committee RMC-1059-20. This work was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No 856487) and by Sagol Institute for Longevity Research in the Weizmann Institute of Science. G.P. is a Zuckerman STEM Leadership Program fellow and thanks them for their support.
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Conceptualization: U.A., R.M., and G.P. Methodology: R.M., G.P., and U.A. Formal analysis: R.M. and G.P. Funding acquisition: U.A. Visualization: R.M. and U.A. Data curation: Y.T. Supervision: U.A. Software: R.M. and G.P. Writing—Original Draft: U.A., R.M., and G.P. Revisions: G.P., U.A., and R.M.
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Moran, R., Pridham, G., Toledano, Y. et al. Pregnancy lab test dynamics resemble rejuvenation of some organs and aging of others. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69340-0
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DOI: https://doi.org/10.1038/s41467-026-69340-0
