Is it permissible to use creams containing urea (carbamide) to conceal pregnancy stretch marks, and are they impure?

The basic principle is that it is permissible to benefit from things, as Allah Almighty says: "He it is Who created for you all that is in the earth." Therefore, there is no harm for women in using creams as long as they are not harmful or impure (najis). If the urea used in the cream is synthetic, it is pure (tahir). If it is natural (najis), it is permissible to use it after it has been treated so that the effects of impurity (color, taste, smell) are removed, or if it has transformed into another pure substance.