What causes my lips to b so dry while pregnant?

Two common reasons: The two most common reasons are #1) a lack of adequate water intake and hydration. # 2) Mouth breathing in late third trimester pregnancy due to the uterus pushing up the diaphragm (breathing muscle) making air intake more difficult. Reason # 2 is solved by improving water intake with reason #1. Finally, chap stick application can avoid lip peeling.