Pregnancy rashes. Rashes of pregnancy include: pruritic urticarial papules and plaques of pregnancy, melasma, prurigo of pregnancy, papular dermatitis of pregnancy, heat rash, pruritic folliculitis of pregnancy, impetigo herpetiformas, and drug eruptions due to medications. See your local doctor for help with the diagnosis as some of the rashes can have side effects.
No. A rash indicates a reaction to an allergen, drug or infection such as a virus or bacteria. It also depends on the nature of the rash (red, bumpy, patchy, itchy, etc) and the location/spread. There is a pregnancy related rash called pupps (aka pep) but that usually happens later in the pregnancy. Go see your obgyn to determine the type of rash and seek appropriate tests, referral to dermatology.