The levels of both oestrogen and progesterone are minimum

In the luteal phase, oestrogen and progesterone are secreted by corpus luteum. As corpus luteum regresses, the levels of oestrogen and progesterone decline leading to menstruation. The levels of oestrogen and progesterone are very low during menstruation phase. During follicular phase, the level of oestrogens increases due to the secretion of oestrogen by the growing follicles.