If you are pregnant and have developed a rash of small red bumps on your belly and breasts, it could be a reaction to a virus. Usually, these rashes do not grow in size and should disappear within a few days. If the rash has remained relatively the same since it first appeared and has been present for less than 5 days, there may be no need to see a doctor. However, it is always a good idea to consult with a pharmacist first to show them the rash and get their opinion on whether a medical consultation is necessary.