The corpus luteum is a small scar or structure that remains at the site of the ovarian follicle
that released an egg during ovulation
. This structure produces progesterone
, the hormones necessary to maintain a pregnancy. If pregnancy does occur, the corpus luteum will continue to function for a few months, providing the necessary hormonal support. If pregnancy does not occur, the corpus luteum simply reabsorbs and stops producing estrogen and progesterone.