World of Oriden
The smaller of Oriden’s moons, Apia (AY-pee-ah) has a cycle of twenty-eight days. The moon is associated with Isis, the goddess of magic and fertility, wife of Mitra the All-powerful. It’s believed this moon strongly influences the fertility cycles of most human females.
A favorite saying of old wives:
When Apia is full a woman is usually at her most fertile.