So Abraham prayed unto God: and God healed Abimelech, and his wife, and his maidservants; and they bore children.
Read Chapter 20
Ephrem The Syrian
Unless Sarah received renewed youth in the seed that she had received, Abimelech would not have desired a woman ninety years old. Then Abraham prayed and God healed Abimelech, his wife and his female slaves so that they bore children, because from the time [Abimelech] had decided to marry Sarah until he returned her, pangs of childbirth struck all the women in his household; they would kneel down, but they could not give birth. ...