The Wedding Date & Chuppat Niddah
Ideally, the wedding should be scheduled for a date when the bride will not be niddah. If this does not work out or is hard to predict, she may choose to adjust her cycle using hormones.
If the bride is niddah at her wedding (chupat niddah), the wedding is valid. A few changes are made discreetly at the ceremony, and the couple may not be alone together (yichud) until after she has immersed.