Bede

They were both old and advanced in years, and it had ceased to be with Sarah after the manner of women. To highlight the growth of heavenly power, he says that both were old, and moreover that Sarah, having been barren, was now also deprived of her menstrual blood, because of which she could no longer conceive, even if she had not been barren. …

Commentary on Genesis (Hexaemeron) ↗