Body fitting compound sanitary napkin having flaps and zone of extensibility

The present invention relates to a compound sanitary napkin comprising a primary absorbent member, a base member, flaps and at least one zone of extensibility. The compound sanitary napkin has a longitudinal center line along a longitudinal direction and a transverse center line along a transverse direction. The primary absorbent member has a longitudinal length, a transverse width, a thickness, a pair of longitudinal sides and a pair of transverse ends, and comprises a primary absorbent element and a fluid pervious cover superimposed on the primary absorbent element. The base member has a longitudinal length, a transverse width, a thickness, a pair of longitudinal sides and a pair of transverse ends, and comprises a fluid pervious body-facing sheet and a fluid impervious garment-facing sheet joined to the fluid pervious body-facing sheet. The primary absorbent member is joined to the base member at least at a part of the longitudinal direction of the primary absorbent member. Flaps extends laterally outwardly from the longitudinal sides of the base member. Each of the flaps has a proximal edge joined with the longitudinal sides of the base member, a distal edge spaced laterally outwardly from the proximal edge. The flaps cover a portion of the leg openings of the wearer's undergarment. At least one zone of extensibility comprises at least a portion of the flaps, wherein at least a portion of the zone of extensibility is spaced longitudinally away from the flap transverse centerline. The entire length of the proximal edge of the flaps is not less than 20% of the length of the primary absorbent member. At least the zone of extensibility is extensible to be capable of a stress given to the flap when the compound sanitary napkin is worn so that the flaps are relatively free from shifting when at least a portion of the primary absorbent member shifts away from the flap.