Delayed puberty is defined as absence of the onset of sexual maturation at the expected time.
The onset of sexual maturation (puberty) takes place when the hypothalamus gland begins to secrete a chemical signal called gonadotropin-releasing hormone. The pituitary gland responds to this signal by releasing hormones called gonadotropins, which stimulate the growth of the sex organs (the testes in boys and the ovaries in girls). The growing sex organs secrete the sex hormones testosterone in boys and estrogen in girls. These hormones cause the development of secondary sex characteristics, including facial hair and muscle mass in boys, breasts in girls, and pubic and underarm hair and sexual desire (libido) in both sexes.
Some adolescents do not start their sexual development at the usual age. In the majority of cases, the delay represents a normal variation, which may run in the family. These adolescents have a normal growth rate and are otherwise healthy. Although the growth spurt and puberty are delayed, they eventually proceed normally.
Various disorders, such as diabetes mellitus, inflammatory bowel disease, kidney disease, cystic fibrosis, and anemia, can delay or prevent sexual development. Development may be delayed in adolescents receiving radiation therapy or cancer chemotherapy. Adolescents, particularly girls, who become very thin because of excessive exercise or dieting often have delayed puberty, including an absence of menstruation.
There are many uncommon causes of delayed puberty. Chromosomal abnormalities, such as Turner's syndrome in girls (see Chromosomal and Genetic Abnormalities: Turner Syndrome) and Klinefelter's syndrome in boys (see Chromosomal and Genetic Abnormalities: Klinefelter Syndrome), and other genetic disorders can affect production of hormones. A tumor that damages the pituitary gland or the hypothalamus can lower the levels of gonadotropins or stop production of the hormones altogether. A mumps infection can damage the testes and prevent puberty.
Delayed puberty is more common among boys and is defined as lack of testicular enlargement by age 14, lack of pubic hair by age 15, or a time lapse of more than 5 years from the start to the completion of genital enlargement. In girls, delayed puberty is defined as absence of breast development by age 13, a time lapse of more than 5 years from the beginning of breast growth to the first menstrual period, or failure to menstruate by age 16.
Although adolescents are typically uncomfortable about being different from their peers, boys in particular are likely to feel psychologic stress and embarrassment from delayed puberty. Girls who remain smaller and less sexually mature than their peers are not stigmatized as quickly as are boys.
The initial evaluation of delayed puberty should consist of a complete history and physical, basic laboratory tests to look for signs of chronic disease, and hormone level tests. A bone age test also may be helpful. Boys under the age of 16 and girls under the age of 14 with delayed puberty who are otherwise healthy most likely have a normal or constitutional delay. For these adolescents, the doctor may elect to reassess at 6-month intervals to ensure that puberty begins and progresses normally. Sometimes a chromosomal analysis may be performed. Girls with severely delayed puberty should be evaluated for primary amenorrhea (see Menstrual Disorders and Abnormal Vaginal Bleeding: Absence of Menstrual Periods). Computed tomography (CT) or magnetic resonance imaging (MRI) may be performed to ensure that there is no brain tumor.
The treatment for delayed puberty depends on its cause. An adolescent who is naturally late in developing needs no treatment, although if the adolescent is severely stressed by the lack of development or development is extremely delayed, some doctors may give supplemental sex hormones to begin the process sooner. If boys show no sign of puberty or bone maturation by age 15, they may be given a 4- to 8-month course of testosterone. At low doses, testosterone induces puberty, causes the development of some masculine characteristics (virilization), and does not jeopardize adult height potential. When an underlying disorder is the cause of delayed puberty, puberty usually proceeds once the disorder has been treated. Genetic disorders cannot be cured, although replacing hormones may help sex characteristics develop. Surgery may be needed for adolescents with tumors.
Last full review/revision January 2009 by Sharon Levy, MD, MPH