When does pregnancy symptoms begins?

After your first missed period.

Actually, some women will experience symptoms not too long after implantation, when hormone levels are on the rise. Some women are more sensitive to these changes in hormones than others. They may start to feel more tired than usual, or notice more headaches, for example.

The difficulty is that some of the possible early pregnancy symptoms can also be experienced prior to an expected period. In fact, many women will say that they feel as though their period is about to start, but it never does.

Women who have been actively trying to become pregnant will often be more aware of these changes if they occur early on. Otherwise, they may be passed off as a period coming or they may not be noticed until later. Some women don't notice anything is really different until weeks into a pregnancy.