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.
However, these doses are massive compared with the very low amount of chemicals a woman is exposed to when colouring her hair. Using hair dye when you're pregnant Many women decide to wait to dye their hair until after the first 12 weeks of pregnancy, when the risk of chemical substances harming the baby is much lower. If you're colouring your hair yourself, you can reduce the risk further by making sure you: 1  wear gloves. 2  leave the dye on for the minimum time. 3  work in a well-ventilated room. 4  rinse your scalp once the dye is applied.