Signaling systems are disclosed that indicate a change in an absorbent article, such as the presence of a body fluid. The various different signaling systems disclosed do not include any conductive elements contained on the interior of the article as were required in the past. Instead, the changes are monitored from the outer cover of the article. In one embodiment, for instance, conductive zones are formed directly into the outer cover for forming the signaling system. Alternatively, a sensor may be mounted to the outer cover of the article for monitoring changes within the article. The sensor may comprise, for instance, a temperature sensor, a conductivity sensor, an optical sensor, a vibration sensor, a humidity sensor, a material expansion sensor, a chemical sensor, or the like.