A system, comprising: a wearable absorbent hygiene article defining a front waist region , a back waist region , a crotch region and a longitudinal axis (L'), the wearable absorbent hygiene article comprising: a liquid permeable top layer adapted to face the wearer during use; a back layer opposite to the top layer; and an absorbent core in the crotch region and located between the top layer and the back layer, the absorbent core having a core length along the longitudinal axis; and a hygiene monitoring device comprising a sensing panel, the sensing panel comprising: an elongate flexible panel defining a longitudinal axis (L) and comprising plates , the plates comprising a pair of plates spaced apart from each other, the plates being disposed on a flexible substrate of the elongate flexible panel, wherein each of the plates is elongate along the longitudinal axis of the elongate flexible panel, wherein the hygiene monitoring device is configured to measure the impedance at at least a predetermined frequency between two of the plates, wherein the extent of the plates along the longitudinal axis of the elongate flexible panel defines a sensing length, and wherein the sensing length is 50% to 100% of the core length, wherein the elongate flexible panel further comprises an insulating layer which entirely covers the plates . a liquid permeable top layer adapted to face the wearer during use; a back layer opposite to the top layer; and an absorbent core in the crotch region and located between the top layer and the back layer, the absorbent core having a core length along the longitudinal axis; and a hygiene monitoring device comprising a sensing panel, the sensing panel comprising: an elongate flexible panel defining a longitudinal axis (L) and comprising plates , the plates comprising a pair of plates spaced apart from each other, the plates being disposed on a flexible substrate of the elongate flexible panel, wherein each of the plates is elongate along the longitudinal axis of the elongate flexible panel, wherein the hygiene monitoring device is configured to measure the impedance at at least a predetermined frequency between two of the plates, wherein the extent of the plates along the longitudinal axis of the elongate flexible panel defines a sensing length, and wherein the sensing length is 50% to 100% of the core length, wherein the elongate flexible panel further comprises an insulating layer which entirely covers the plates . an elongate flexible panel defining a longitudinal axis (L) and comprising plates , the plates comprising a pair of plates spaced apart from each other, the plates being disposed on a flexible substrate of the elongate flexible panel, wherein each of the plates is elongate along the longitudinal axis of the elongate flexible panel, wherein the hygiene monitoring device is configured to measure the impedance at at least a predetermined frequency between two of the plates, wherein the extent of the plates along the longitudinal axis of the elongate flexible panel defines a sensing length, and wherein the sensing length is 50% to 100% of the core length, wherein the elongate flexible panel further comprises an insulating layer which entirely covers the plates . <EOS>