01985nas a2200337   4500000000100000000000100001008004100002260001500043653001700058653001500075100002600090700003200116700002500148700002200173700002700195700001500222700001900237700001800256700001700274700001600291700001800307700001700325700001900342700002000361245011200381856005500493300000800548490000700556520107000563022001401633       2025                            d  c2025-01-1610aNeuroscience10aPsychology1 aCamila Servin-Barthet1 aMagdalena Martínez-García1 aMaría Paternina-Die1 aLuis Marcos-Vidal1 aDaniel Martín de Blas1 aAnna Soler1 aOlha Khymenets1 aDaniel Bergé1 aGemma Casals1 aPilar Prats1 aOscar J. Pozo1 aClara Pretus1 aSusana Carmona1 aOscar Vilarroya00aPregnancy entails a U-shaped trajectory in human brain structure linked to hormones and maternal attachment  uhttps://www.nature.com/articles/s41467-025-55830-0  a7300 v163 aGrowing evidence places the gestational period as a unique moment of heightened neuroplasticity in adult life. In this longitudinal study spanning pre, during, and post pregnancy, we unveil a U-shaped trajectory in gray matter (GM) volume, which dips in late pregnancy and partially recovers during postpartum. These changes are most prominent in brain regions associated with the Default Mode and Frontoparietal Network. The U-shaped trajectory is predominantly linked to gestational factors, as it only presents in gestational mothers and correlates with fluctuations in estrogens over time. Finally, the mother’s mental health status mediates the relationship between postpartum GM volume recovery and maternal attachment at 6 months postpartum. This research sheds light on the complex interplay between hormones, brain development, and behavior during the transition to motherhood. It addresses a significant knowledge gap in the neuroscience of human pregnancy and opens new possibilities for interventions aimed at enhancing maternal health and well-being.  a2041-1723