This 2023 primate study investigated the body’s capability to remember prenatal experiences influencing later life:

“Maternal stressors and other environmental factors affect the developing embryo and fetus in ways that lead to increased susceptibility for chronic disease in later life. Developmental programming of chronic low-grade inflammation plays an important role in onset and progression of these diseases.

Establishing innate immune cell memory involves increased glycolysis, reduced oxidative phosphorylation, and expression of transcription factors which prime for pro-inflammatory activity. This memory relies on propagation of epigenetic modifications that develop in hematopoietic stem and progenitor cells (HSPCs), which can be passed on to progeny immune cells (i.e., macrophages).

These changes persist with altered epigenetic regulation for years after weaning – even when offspring are fed a conventional diet – predisposing offspring to inflammatory disease across their lifespans.

Several factors may initiate metabolomic reprogramming in fetal HSPCs:

• We found increased chromatin accessibility of gene regulatory regions and RNA signatures supporting activation of factors with a major role in regulating macrophage inflammatory activation, including FOS/JUN, NF-κB, C/EBPβ, and STAT6.
• Our prior work demonstrated a persistently altered histone code in liver tissue from juvenile animals.
• Maternal diet-supplied lipids, including oleic acid, in hematopoietic tissues may play an important role in priming inflammation and metabolism in fetal HSPCs and bone marrow-derived macrophages with postnatal persistence.

Striking changes in fetal bone marrow and liver HSPCs observed here suggest that the primary driver for developmental programming of inflammation takes place in utero. However, we cannot rule out that exposure to maternal diet during lactation postnatally triggers shifts in microbiome composition or function contributing to inflammation.

Components of maternal diet, rather than maternal obesity per se, are a modifiable risk factor with potential to alter developmental programming of offspring immune systems.”

https://www.cell.com/cell-reports/fulltext/S2211-1247(23)00404-7 “Maternal diet alters long-term innate immune cell memory in fetal and juvenile hematopoietic stem and progenitor cells in nonhuman primate offspring”

And there are other ways we remember everything that happened then and along the way. Big clues are in our out-of-context responses to present day events.