Additional emphasis should be placed on the abdominal examination—palpating for a uterine fundus, suprapubic and/or lower quadrant tenderness Particular attention should be placed on pelvic examination, which consists of visualizing the external genitalia, performing the bimanual examination, and using a speculum to visualize the vaginal vault and cervix Visualization of the external genitalia allows the clinician to verify the origin of the bleeding, assign Tanner pubertal staging, and assess for signs of virilization, trauma, or discharge For adolescents with more significant blood loss, anemia, or concerns for sexually transmitted infection, the examination then includes a bimanual examination to assess for the presence of a vaginal foreign body or mass and to determine cervical motion, uterine, and/or adnexal tenderness The speculum examination may be reserved for girls who have significant, ongoing blood loss as this procedure is perceived as relatively invasive by many teens NAAT testing on urine has become the standard thus collecting swabs is usually not necessary FIGURE 79.3 Diagnostic approach to abnormal uterine bleeding after menarche—nonpregnant patients Universal pregnancy testing is recommended for all adolescent girls presenting with abnormal bleeding Often teens not feel comfortable disclosing their sexual history Uterine bleeding in the pregnant patient is an obstetric emergency A complete blood count (CBC) with differential is also recommended for teens presenting with heavy bleeding because estimates of blood loss based on pad or tampon use are typically inaccurate Given the prevalence of sexually transmitted infection in this age group, screening for Chlamydia trachomatis and N gonorrhoeae via nucleic acid amplification testing of the urine or vaginal swab is recommended Further evaluation for bleeding disorders and/or endocrine causes is indicated based on clinical suspicion Coagulation studies such as prothrombin time (PT)/thromboplastin time (PTT), fibrinogen, von Willebrand assay (includes von Willebrand factor antigen, ristocetin cofactor assay, and factor VIII), and bleeding time may be helpful in patients with heavy cyclical bleeding from menarche and those with more severe degree of anemia (hemoglobin less than 10 mg/dL) Von Willebrand studies, however, may be misleadingly normal during acute bleeding or in the presence of estrogen Endocrine studies may be considered including TSH, prolactin, dehydroepiandrosterone sulfate (DHEAS), testosterone profile, androstenedione, and 17-hydroxyprogesterone Consultation with adolescent, hematology, and endocrine specialists can be considered as clinically indicated Causes of Uterine Bleeding in the Adolescent Patient The differential diagnosis of abnormal genital bleeding is broad, and one must consider all the diagnostic possibilities during the evaluation For the vast majority of adolescents evaluated in the ED for excessive bleeding, the most common causes are anovulation, usually related to immaturity of the hypothalamic–pituitary–gonadal axis or polycystic ovarian syndrome, and sexually transmitted infection It is crucial to evaluate for pregnancy-related conditions early in all postpubertal girls with bleeding, even if sexual activity is denied Vaginal bleeding may be the result of accidental injury or trauma from either a consensual or abusive relationship A foreign body such as a retained tampon or an intrauterine device may cause abnormal bleeding Rare causes include hematologic disorders, thyroid or adrenal disease, prolactinomas, or another central nervous system neoplasm Structural abnormalities of the reproductive tract such as uterine fibroids or polyps are highly unusual causes in the adolescent age group (see Table 79.2 ) TABLE 79.2 DIFFERENTIAL DIAGNOSIS OF ADOLESCENT ABNORMAL UTERINE BLEEDING Anovulation Hypothalamic–pituitary–gonadal axis immaturity Polycystic ovarian disease Hormonal contraceptives Pregnancy Threatened, spontaneous, or missed abortion Placenta previa, placenta accretia Ectopic pregnancy Infection Cervicitis (especially chlamydial) Pelvic inflammatory disease Trauma Laceration Sexual abuse Foreign body Hematologic Von Willebrand disease, platelet dysfunction Thrombocytopenia Coagulation defects, factor deficiencies Endocrine Polycystic ovarian syndrome Thyroid disorders Adrenal disorders Hyperprolactinemia Endocrine Endocrinologic phenomena—whether physiologic, pharmacologic, or pathologic —are the most common causes of AUB in nonpregnant adolescents During physiologically normal menstrual cycles, the occasional adolescent has spotty bleeding for 24 hours or less in association with the transient decline in estrogen level that occurs at midcycle The unilateral pain of mittelschmerz can accompany this brief bleeding episode Hormonal contraception is a common, pharmacologic cause of irregular menstrual bleeding Of women who use birth control pills containing 35 μg or less of estrogen, 5% to 10% will have breakthrough intermenstrual spotting or bleeding, especially during the first months of contraceptive pill use Breakthrough bleeding is also a common side effect of progestin-only contraceptive pills, injectable medroxyprogesterone, and long-acting progestin implants Many patients using birth control pills experience estrogen and progesterone withdrawal bleeding if they forget to take one or several pills Physiologic anovulatory cycles are frequent, especially in the first years after menarche, stemming from immaturity of the hypothalamic–pituitary–ovarian axis The physiology of anovulatory cycles deserves special mention as it is one of the most common causes of irregular bleeding in adolescents In the absence of ovulation, the corpus luteum never forms, and estrogen continues to act on the endometrium unopposed by progesterone The lining becomes increasingly thicker and eventually outgrows the supporting capabilities of the stroma Punctate areas of endometrial shedding give way to more significant bleeding as the deeper layers are affected and the spiral arterioles are exposed The treatment of AUB from physiologic anovulation requires the administration of both exogenous estrogen and progesterone—estrogen to stimulate endometrial regrowth in the excessively thin areas and progesterone to strengthen the stromal support Anovulatory cycles caused by polycystic ovarian syndrome should also be considered in a teenager with AUB Menstrual cycles may be infrequent and irregular, as androgenic excess contributes to abnormal ovarian function and anovulation Polycystic ovarian syndrome is common among adolescents and should be considered in adolescents with abnormal bleeding and stigmata of androgen excess (hirsutism, acne, obesity) Hypothyroidism should be considered if the patient has other symptoms or signs of thyroid dysfunction A functioning ovarian cyst is a less common cause of vaginal bleeding but should be considered especially in the teenager with AUB and an adnexal mass or tenderness Infection In the nonpregnant patient with AUB, infectious causes such as cervicitis or pelvic inflammatory disease should be considered, especially if there is pelvic pain or tenderness Abnormal bleeding occurs in nearly one-third of patients with pelvic inflammatory disease, generally as a result of endometritis Sexually transmitted infections and pelvic inflammatory disease are discussed in detail in