This study presents a novel intravital imaging technique for longitudinal monitoring of mouse placental development and function. The researchers developed an implantable placenta window that allows high-resolution photoacoustic and fluorescence imaging of the placenta throughout pregnancy. The window is optically and acoustically transparent, enabling detailed imaging of placental hemodynamics and molecular activities. The study also demonstrates the use of ultrafast functional photoacoustic microscopy (UFF-PAM) to achieve high-speed, high-resolution imaging of placental vasculature and oxygenation levels. The placenta window was implanted in pregnant mice on embryonic day 7.0 (E7.0) and remained functional throughout pregnancy. The window allowed for longitudinal imaging of placental development without affecting the fetus's organ formation, delivery, or feeding. However, embryos under the window showed reduced weight, possibly due to heat loss or pressure from the window. The window was made of biocompatible titanium alloy and did not induce inflammation or tissue damage. The study used UFF-PAM to monitor placental hemodynamics during healthy pregnancy, revealing changes in vessel diameter, vessel density, and blood oxygenation levels. The placenta underwent significant vascular remodeling during pregnancy, with vessel diameter increasing initially and then decreasing toward the end of pregnancy. Blood oxygenation levels increased during the first trimester and then decreased as delivery approached. The study also examined the effects of alcohol consumption and cardiac arrest on placental hemodynamics. Alcohol consumption induced hyperperfusion and elevated oxygenation levels, which may have adverse effects on embryonic development. Cardiac arrest caused hypoperfusion and hypoxia, leading to reduced blood oxygenation and vessel dilation. Inflammation, induced by lipopolysaccharide (LPS), disrupted placental vasculature and reduced microvessel density, potentially contributing to pregnancy complications. The study also demonstrated the use of the placenta window for tracking viral transduction and chemical diffusion. Adeno-associated viruses (AAVs) were used to deliver genes into the placenta, and fluorescent markers were used to track their diffusion. The placenta window allowed for high-resolution imaging of these processes at the single-cell level. The study highlights the importance of placental function in pregnancy and the need for advanced imaging techniques to understand placental development and its role in pregnancy complications. The developed intravital imaging platform provides a powerful tool for studying placental biology and could be applied to other areas of reproductive medicine.This study presents a novel intravital imaging technique for longitudinal monitoring of mouse placental development and function. The researchers developed an implantable placenta window that allows high-resolution photoacoustic and fluorescence imaging of the placenta throughout pregnancy. The window is optically and acoustically transparent, enabling detailed imaging of placental hemodynamics and molecular activities. The study also demonstrates the use of ultrafast functional photoacoustic microscopy (UFF-PAM) to achieve high-speed, high-resolution imaging of placental vasculature and oxygenation levels. The placenta window was implanted in pregnant mice on embryonic day 7.0 (E7.0) and remained functional throughout pregnancy. The window allowed for longitudinal imaging of placental development without affecting the fetus's organ formation, delivery, or feeding. However, embryos under the window showed reduced weight, possibly due to heat loss or pressure from the window. The window was made of biocompatible titanium alloy and did not induce inflammation or tissue damage. The study used UFF-PAM to monitor placental hemodynamics during healthy pregnancy, revealing changes in vessel diameter, vessel density, and blood oxygenation levels. The placenta underwent significant vascular remodeling during pregnancy, with vessel diameter increasing initially and then decreasing toward the end of pregnancy. Blood oxygenation levels increased during the first trimester and then decreased as delivery approached. The study also examined the effects of alcohol consumption and cardiac arrest on placental hemodynamics. Alcohol consumption induced hyperperfusion and elevated oxygenation levels, which may have adverse effects on embryonic development. Cardiac arrest caused hypoperfusion and hypoxia, leading to reduced blood oxygenation and vessel dilation. Inflammation, induced by lipopolysaccharide (LPS), disrupted placental vasculature and reduced microvessel density, potentially contributing to pregnancy complications. The study also demonstrated the use of the placenta window for tracking viral transduction and chemical diffusion. Adeno-associated viruses (AAVs) were used to deliver genes into the placenta, and fluorescent markers were used to track their diffusion. The placenta window allowed for high-resolution imaging of these processes at the single-cell level. The study highlights the importance of placental function in pregnancy and the need for advanced imaging techniques to understand placental development and its role in pregnancy complications. The developed intravital imaging platform provides a powerful tool for studying placental biology and could be applied to other areas of reproductive medicine.