A girls first period was a time for celebration, she would be lavished with gifts from her family and given a feast before retiring to the Red Tent. There she would find food and anything she needed to pass the time, and often be accompanied by her mother or another female family member to guide her. Often farmers would bring female livestock to the Red Tent to ask for the women inside to bless them, therefore increasing the chance of the animal producing offspring.
Using menstural blood in Magick is a very old, very sacred tradition. For fertility draw a sigil on a egg using menstural blood. Bury under a apple tree. Eating the apples will aid your fertility.