Puberty represents a particular period of life characterized by hormonal changes and physical and psychological modifications leading children from childhood to adolescence. During this period, menarche represents the most important event in females. Age of menarche is different among populations and has been recognized as an useful marker of socio-economic status, as well as dietary and environmental patterns (Chumlea et al., 2003; Swenson & Havens, 1987; Thomas et al., 2001). Generally, the first menstrual cycle takes place between 12 and 13 years of age, with 98% of girls having menarche by 15 years of age (Diaz, 2006). The normal range for menstrual cycles is between 21 and 45 days, with flow length varying from 2 to 7 days (Flug et al., 1984; World Health Organization Task Force on Adolescent Reproductive Health, 1986). During the first 2 years after menarche, menses length is often abnormal due to immaturity of the hypothalamic-pituitary-ovarian axis (Diaz, 2006); however, cycles range can be regular also in the first gynecologic year (Flug et al., 1984; World Health Organization Task Force on Adolescent Reproductive Health, 1986). Amenorrhea is defined as the complete absence or anomalous cessation of menstrual cycles in females during reproductive years. Just in three situations amenorrhea is considered physiological: during pregnancy, lactation and menopause. In all other situations, amenorrhea can be due to many pathological conditions and merits a careful assessment. Amenorrhea is classified as primary and secondary according to its occurrence before or after menarche, respectively (The Practice Committee of American Society for Reproductive Medicine, 2008). Amenorrhea is defined primary when menarche does not occur by the age of 16 years in a girl with complete secondary sexual development, or by the age of 14 years in a girl without secondary sexual development. Amenorrhea is defined secondary when menstrual cycles disappear for 6 consecutive months in a girl with irregular menses or for 3 consecutive months in a girl with regular menses (Deligeoroglou et al., 2010). According to the American Society for Reproductive Medicine, currently in literature many causes of amenorrhea have been recognized (The Practice Committee of American Society for Reproductive Medicine, 2008), including: • anatomic defects of the genital tract • hypothalamic/pituitary causes • ovary insufficiency • endocrinopathies • chronic oligoor anovulation