Douglas Harper's Etymology Dictionary
luteal
"pertaining to the corpus luteum," 1906, from Latin luteus "yellow" (see luteous). Luteal phase is attested by 1932.
Wiktionary
luteal
a. Of or pertaining to the corpus luteum
WordNet
luteal
adj. of or relating to the corpus luteum
Wikipedia
Usage examples of "luteal".
And secretions collected in the luteal phase, in the days before menstruation, had no effect whatsoever.