An absorbent core comprising an absorbent material between a top core wrap sheet and a back core wrap sheet, said absorbent core having a first and second longitudinal edge and a first and second transverse edge, wherein the absorbent core is provided with at least a first elongated attachment zone where the top core wrap sheet is attached to the back core wrap sheet, said first attachment zone has a first width (w1) at a first position and a second width (w2) at a second position, wherein the first width is larger than the second width.
