The invention relates to a vaginal fluid monitoring device embedded into a feminine sanitary pad, said device comprising a stack of the following elements: An absorbent layer (100) configured to be in proximity to, and collect, a vaginal fluid; and A biosensing system (1000) in fluidic connection with said absorbent layer (100), said biosensing system (1000) comprising: A microfluidic chip (200) configured to perform an immunoassay to detect the presence and/or the concentration of at least one target biomarker comprised in a vaginal fluid; Means (300) for providing a readout of the presence and/or the concentration of said at least one target biomarker; and An electrode array (400) located along the microfluidic chip (200) configured to detect and analyze the flow of said vaginal fluid by impedance means; wherein said immunoassay is configured to detect the presence and/or the concentration of at least one target biomarker indicative of a pre-term birth (PTB) risk and/or premature rupture of membrane (PROM) risk. The invention also relates to a method for detecting at least one target biomarker comprised in a vaginal fluid.