I'm not sure if there is a definite medical reason why a pregnant woman's sense of taste and smell fluctuates during pregnancy, but it is very common. Many women find they are nauseated by familiar and previously enjoyed odours, tea and coffee are common, in tandem with cravings for certain tastes or foods, often in large amounts. The good news for fathers like me who once spent several hours finding a peterol station in the middle of the night that sold polo mints, and for afflicted mums-to-be such as yourself, is that these sensations appear to cease once baby arrives, and do not normally return. Hang in there, good luck with your new baby.