This application relates to the use of slitted regions in absorbent members formed of absorbent materials that remain relatively thin until wetted with such fluids. Suitable materials include presently preferred varieties of polymeric foam materials. Single and multi-layered absorbent members incorporating slitted regions are disclosed, as well as the use of pre-formed cup-shaped slits for enhanced initial fluid acquisition. Such slitted regions in combination with planar expansion properties enable the absorbent members to respond dynamically to various fluid loading conditions to create useful structural features. The slitted regions, in combination with absorbent materials having expansion potential in at least one direction within the plane of the absorbent member, cause the slitted regions to buckle and/or deform out of the plane of the absorbent member, thereby causing the slit surfaces to displace angularly and/or translationally with respect to one another. This more fully exposes the slit surfaces to the incoming fluid for improved acquisition capabilities. The use of pre-formed cup-shaped slits enables the absorbent member to more quickly capture and absorb aqueous body fluids, and is particularly useful for containment and dewatering of moist or runny fecal material and higher viscosity fluids and/or those having a higher concentration of particulate material therein such as blood, menses, or wound fluids.