The females of most barb species become deeper in the body and noticeably wider when viewed from above as they mature. Unless the fish is showing signs of distress, or the deepening is uneven, (i.e. a lump on one side etc.), you needn't worry about it.
Females will often drop a few eggs in a ciommunity tank. These rarely survive long, the other fish in the tank will eat them. Any that survive, that had been fertilised may hatch if your water is soft enough, but the fry are very small and stand no real chance.
To breed egglayers, you really need special breeding set-ups.