The main difference between the nitrogen used by a doctor and the nitrogen in over-the-counter products like Freeze Away is the temperature at which they can reach. The liquid nitrogen used by a doctor can reach -50°C in just 30 seconds, whereas the products available at stores do not get as cold as quickly. It is important to note that over-the-counter products have been associated with cases of frostbite due to mishandling at home. It is always advisable to consult a healthcare professional before using any treatment during pregnancy, as many over-the-counter medications may not have been studied specifically in pregnant women. It is generally recommended to opt for treatments like liquid nitrogen or salicylic acid-based products that are known to be safer during pregnancy.