Neural Control of Blood Volume Expansion During Pregnancy

Pregnancy induces profound adaptations of the vascular system. Under normal conditions, maternal blood vessels dilate, and blood volume expands to deliver oxygen to maternal and fetal organs. In preeclampsia—a serious vascular disorder and leading cause of maternal mortality—blood volume is reduced, suggesting a link with pregnancy-related vascular disorders. Unfortunately, our understanding of vascular function during pregnancy has been limited to peripheral tissues. My objective is to determine how the brain coordinates blood volume expansion during pregnancy. I am focused on the subfornical organ (SFO) of the hypothalamus, a critical sensory brain nucleus that regulates thirst and fluid homeostasis. I hypothesize that sensory neuron populations of the SFO play an essential role in detecting and regulating maternal blood volume during pregnancy. Using mice, I find that, similar to humans, maternal blood volume doubles by late-stage pregnancy, as does the significant upregulation of hormonal signaling pathways in SFO neurons. The change in hormonal pathways suggests increased neuronal activity in this brain region, which may differentially regulate blood volume during pregnancy. To assess the functional role of these neurons, in vivo chemogenetics will be used to inhibit candidate populations during pregnancy, which is expected to prevent pregnancy-induced blood volume expansion and to reduce fecundity and maternal health. Understanding the brain’s role in vascular adaptation during reproduction will improve our understanding of maternal and fetal health and suggest possible options for treating gestational and peripartum vascular disorders. This work is funded by the UCSF Sandler PBBR New Frontiers Award. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.