The physical changes that takes place in the females is termed as menstrual cycle; once a female reaches the age of puberty the cycle begins and continues till menopause. Generally the cycle starts at the age of 12 and continues up to the age of 51.   The first menstruation which occurs in female are called menarche; the age of menarche may vary from 8 years to 16 years but 12 is considered to be the average age.  Similarly average menopause age is 51 years but can vary from 40 years to 58 years.

The menstrual cycle forms an important part in the reproductive cycle of any woman and is influenced by the hormonal activity of the body. The traditional view linked it to the cycle of the moon. When there is new moon the women menstruate while ovulation occurs during full moon. The different phases of the cycle include menstrual phase, luteal phase, follicular phase and ischemic phase.

During menstruation bleeding occurs through the vagina.  The phase is an indication that pregnancy has not occurred in the woman; however bleeding during the early stages of pregnancy might be possible. Follicle stimulating hormone influences the follicular phase; it is also responsible for the production of estradiol and estrogen which in turn is responsible for stimulating crypts in cervix.  Mature egg causes the release of luteinizing hormone; some women may experience little pain during the period and some bleeding might also take place.

Estrogen and progesterone are the two sex hormones which plays a major in menstrual cycle.  Estradiol produced by estrogen is highly active during the luteal phase and also during the follicular growth. Progesterone plays a significant role during the pregnancy and also during the luteal phase. Normal menstrual cycle is a must for overall well being of any woman.