Menstrual cups are a safe option relative to other forms of menstrual hygiene. Innumerable Victorian women were prescribed the drug for relief of menstrual cramps and vague aches. Pain in contractions has been described as feeling similar to very strong menstrual cramps. Furthermore, prolactin levels vary according to factors as age, sex, menstrual cycle stage and pregnancy. Spironolactone produces an irregular and anovulatory pattern of menstrual cycles. Women will often stop having menstrual periods. It secretes hormones that influence stages of the menstrual cycle. Women's hormone also changes due to the menstrual cycle. They can also secrete hormones which change the menstrual cycle. Functional cysts form as a normal part of the menstrual cycle. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Other normal temperature variations include those related to the menstrual cycle. Behavior towards potential mating partners changes during different phases of the menstrual cycle. An enzyme called plasmin inhibits clotting in the menstrual fluid. It works with estrogens in establishing the menstrual cycle.