The Francis Crick Institute conducted research into how hormones influence brain function during pregnancy, revealing that the body’s own signals can prime parental behavior even before any offspring appear. The findings, published in Science, highlight a hormonal system that reshapes neural circuits in anticipation of parenthood.
Researchers report that hormones such as estrogen and progesterone play a key role in reprogramming the brain during late pregnancy. In experiments with laboratory mice, female mice showed an uptick in caregiving behaviors as pregnancy progressed, and this shift did not depend on the presence of newborns to occur. The results suggest that the brain is already preparing for parenthood well before birth, aligning maternal behavior with the coming responsibilities of caring for an infant.
A focal point of the study is a cluster of nerve cells in the hypothalamus, a brain region long linked with social behavior and parenting. These neurons are directly exposed to estrogen and progesterone during pregnancy, and the hormonal influence appears to reorganize the neural networks involved in care and nurturing.
Brain imaging revealed that estrogen lowers the baseline activity of these hypothalamic neurons while increasing their excitability in response to signals. At the same time, progesterone adjusts the way these neurons process incoming information, effectively remapping how they respond to stimuli related to offspring. By modulating sensitivity to these hormones, researchers were able to suppress parental behavior in pregnant mice, resulting in animals that could not care for offspring even after birth.
The team believes that a comparable brain reorganization may occur in humans during pregnancy, given that the same hormonal shifts impact the same brain regions. If similar patterns hold, hormonal changes could influence parental responses in expectant mothers, shaping how attention, bonding, and caregiving are expressed after delivery.
Previous work in this field has explored connections between a woman’s reproductive life and brain health, underscoring a broader view of how hormonal cycles, pregnancy, and aging influence cognitive and emotional function. The current findings add a compelling layer to this understanding by showing a direct mechanistic link between hormonal signaling during pregnancy and the emergence of parenting behaviors in model systems, with potential implications for human biology and psychiatry.
Overall, the research points to hormones as active agents that prepare the brain for the demands of parenthood. By shaping neural circuits in regions tied to emotion, motivation, and social bonding, estrogen and progesterone may help explain why some new parents show immediate sensitivity to infant cues and a rapid onset of caregiving actions, even before a child is present. The study contributes to a growing body of evidence that the brain is not a passive organ during pregnancy, but a dynamic system capable of remodeling itself in anticipation of family life.