Short and Long Term Effects of Pregnancy on the Brain
Dr. Galea has been studying how reproductive experience affects the hippocampus since 2000 (funded in part by CIHR and Alzheimer Society of Canada) and how different estrogens impact the hippocampus since 2003. A review of our work and others explains quite a bit of the fascinating effects of pregnancy on the brain (Puri, Richard, Galea, 2023).
We found short and long-term effects on hippocampus structure and function after parturition (Galea et al., 2018; Duarte-Guterman et al., 2019). In the short term, primiparity decreases hippocampus neurogenesis (Pawluski & Galea 2007, Eid et al., 2019) & CA1 CA3 dendritic architecture (Pawluski & Galea, 2007; Workman et al., 2013). However, at the same time, we found enhanced working memory in primiparous rats (Pawluski et al., 2006). It may seem paradoxical that coincident with significant hippocampus dendritic pruning primiparous rats have better spatial performance, but the same relationship is seen in chronically stressed female rats. Reactive hippocampus microglial and increased cytokines (Eid et al., 2019) are present in the early postpartum. Fascinatingly, we see changes to the aging trajectory of cytokine signaling and neurogenesis with parity that extends to middle age (Eid et al., 2019; Richard et al., in prep). Estradiol and estrone increase proliferation in multiparous but not nulliparous rats (Barha and Galea, 2011), and Premarin enhanced learning in nulliparous, but reduced learning in primiparous middle-aged rats (Galea et al., 2018). Our work in this area is based on our promising data that parity alters the trajectory of hippocampus aging (Eid et al., 2019; Barha et al., 2015; Duarte-Guterman, Richard et al., submitted), transcriptome (Duarte-Guterman et al., 2018 abstract) and the ability of hormone therapies to influence learning and neuroplasticity (Barha and Galea, 2011; Galea et al., 2018). Next, we will be examining how genotype may influence the effect of parity on aging.
