That answer can definetly vary from woman to woman. Some women start to look pregnant in their 3rd month, especially if they have had children before. Some woman don’t look pregnant until their 5th or 6th month. I have heard stories where some women didn’t show until their 3rd trimester. It depends on your body shape and the way your baby is laying in your womb. I would say the average is month 4 that you may have to start to wear some maternity clothes.