Carbon dioxide. Carbon dioxide (chemical formula CO2) is a colorless gas with a density about 60% higher than that of air (1.225 g/L) that is odorless at normally encountered concentrations. Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms.
You should only do ballet in pregnancy if you are used to it. Ballet stretches can place a lot of pressure on your joints, especially your pelvic joints, and standing on one leg can cause pain in your pelvis.
It's not uncommon to experience episodes of dizziness and fainting while pregnant, especially in your first and second trimesters. While there are many different reasons, if you are dizzy while pregnant you may have stood up too quickly or stood for a long period of time.