You get much more mercury from these sources than from your amalgam fillings. This is extremely rare. Only 46 cases have been reported throughout the world since 1905. If you are worried, ask your doctor to refer you to a specialist for tests to check if you are allergic. If so, your dentist can use another type of filling for you.
Alternatives exist but some can be rather expensive.
The World Health Organisation says that it is safe to use. Unless you are one of those rare individuals who is particularly sensitive to dental amalgam, you will not improve your dental health by having these fillings replaced. Australia s specialist doctors and Health authorities have warned the public that there is no justification for believing that this will cure a range of serious illnesses. It is always sound practice to avoid any unnecessary dental treatment during pregnancy, including any dental fillings. Your dentist may be able to put off your treatment to a more suitable time.