<P> Painful cramping in the abdomen, back, or upper thighs is common during the first few days of menstruation . Severe uterine pain during menstruation is known as dysmenorrhea, and it is most common among adolescents and younger women (affecting about 67.2% of adolescent females). When menstruation begins, symptoms of premenstrual syndrome (PMS) such as breast tenderness and irritability generally decrease . Many sanitary products are marketed to women for use during their menstruation . </P> <P> The proliferative phase is the second phase of the uterine cycle when estrogen causes the lining of the uterus to grow, or proliferate, during this time . As they mature, the ovarian follicles secrete increasing amounts of estradiol, and estrogen . The estrogens initiate the formation of a new layer of endometrium in the uterus, histologically identified as the proliferative endometrium . The estrogen also stimulates crypts in the cervix to produce fertile cervical mucus, which may be noticed by women practicing fertility awareness . </P> <P> The secretory phase is the final phase of the uterine cycle and it corresponds to the luteal phase of the ovarian cycle . During the secretory phase, the corpus luteum produces progesterone, which plays a vital role in making the endometrium receptive to implantation of the blastocyst and supportive of the early pregnancy, by increasing blood flow and uterine secretions and reducing the contractility of the smooth muscle in the uterus; it also has the side effect of raising the woman's basal body temperature . </P> <P> While some forms of birth control do not affect the menstrual cycle, hormonal contraceptives work by disrupting it . Progestogen negative feedback decreases the pulse frequency of gonadotropin - releasing hormone (GnRH) release by the hypothalamus, which decreases the release of follicle - stimulating hormone (FSH) and luteinizing hormone (LH) by the anterior pituitary . Decreased levels of FSH inhibit follicular development, preventing an increase in estradiol levels . Progestogen negative feedback and the lack of estrogen positive feedback on LH release prevent a mid-cycle LH surge . Inhibition of follicular development and the absence of a LH surge prevent ovulation . </P>

What is the function of the female menstrual cycle