The production of cervical mucus is stimulated by
Cervical mucus is a glycoprotein gel that expand and contract in response to cyclic changes in the steroid hormone environment across the menstrual cycle to facilitate or inhibit the passage of sperm

Estrogen stimulates cervical mucus production, and as levels rise during the follicular phase, mucus becomes more abundant and watery, less cellular, and more easily penetrated by sperm
Progesterone inhibits cervical mucus production and renders it opaque, viscid, and impenetrable
Progesterone
Pregnenolone
Estriol
Estradiol