Moira Foy was Aislinn’s mother and Elena’s daughter. Like her mother and daughter, she was gifted with the Sight. Keenan courted her but she was frightened of him, since she saw him as he really was. The history of Keenan’s courtship of her is not clear but she tried to escape Keenan and slept around with other men until she became pregnant. That was when Keenan left her alone, planning to come back after the birth.
Moira died after giving birth to Aislinn, but the cause of death is not mentioned in Wicked Lovely. Aislinn had been told she died in childbirth and Keenan said that she chose death rather than becoming a Summer Girl. This could mean two things. Either Moira killed herself or it was made clear that the birth would kill her. Moira was the only girl courted by Keenan who never got to choose between being a Summer Girl or trying the test with the Winter staff, but death was the escape she took.