Amenorrhea and oligomenorrhea in the adolescent female are often the result of anovulation due to an immature hypothalamic-pituitary-ovarian axis. A careful history, physical examination and selected laboratory tests can help to differentiate this type of transient menstrual irregularity from the large number of endocrine and anatomic abnormalities that also present in this age group.
PIP: The workup of the adolescent with menstrual dysfunction is directed toward separating the "functional" irregular menstrual pattern of an immature hypothalamic/pituitary/ovarian (HPO) axis from the large number of endocrine and anatomic abnormalities that can become manifest in this age group. The HPO axis is not fully mature at menarch. Since the positive feedback response to estrogen, which allows ovulation, is frequently absent in the immediate postmenarchial peroid, menstrual irregularity is common. 55% of cycles are anovulatory in the 1st year. With futher maturation of the HPO axis a pattern of regular ovulatory cycles emerges, and in women 11 years after menarche by age 18 but a basic evaluation is indicated if menarche does not occur by age 16 or if secondary sexual development does not being by age 14. Secondary amenorrhea is the absence of menses for at least 3 months in a patient who previously had established cycles. With the exception of anatomic abnormalities of the lower reproductive tract that result in primary amenorrhea exclusively, there is considerable overlap between the differential diagnosis of primary and secondary amenorrhea. Causes of amenorrhea in adolescents are pregnancy, drugs and systemic diseases, hypothalamic and pituitary amenorrhea, "postpill" amenorrhea; hyperprolactinemia, androgen resistance, congenital anomalies of the genital tract, and androgen excess. Despite the large number of disorders that can cause menstrual abnormalities, the initial workup of the patient who presents with amenorrhea or delayed development can be simplified to a careful history, physical examination, and a few screening laboratory tests. The adolescent who has no development by age 14 or no menarche by age 16, whose menses cease for 4 months or more, or who has persistent oligomenorrhea or signs of androgen excess deserves an evaluation. Since the option of 1st trimester therapeutic abortion depends on early diagnosis of unwanted pregnancy, this diagnosis should be excluded without delay. The history should include: neonatal history -- maternal ingestion of virilizing hormones, previous maternal miscarriages, congenital lymphedema; family history -- heights of family members, age at menarche and fertility of female family members, and history of endocrine disorders; growth and pubertal developments; past medical history -- chronic disease, congenital anomalies, previous surgery, radiation exposure, chemotherapy, or drug use; and review of symptoms. The physical examination should include: height, weight, arm span, blood pressure; assessment of sexual maturity; and endocrine and gynecologic assessment. The screening tests for the patient with amenorrhea include urinary HCG, complete blood count, sedimentation rate, thyroid function, prolactin, FSH and LH, and assessment of estrogen status.