The period leading up to Tisha B'Av, the fast day commemorating the destruction of the Temple, is a time of communal mourning.
Although bathing for pleasure is prohibited before Tisha B'Av (either from the beginning of Av or during the week in which Tisha B'Av falls, depending on custom), a woman may prepare for mikveh normally during this period. She should not spend extra time luxuriating in the bath. On Tisha B'Av itself, one may neither prepare nor immerse in the mikveh.
There is debate among halachic authorities as to whether a woman may remove body hair during the three weeks before Tisha B'Av, so it is best to ask an individual question.
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