What workup should be considered for a 20-year-old female with frequent menstrual cycles (oligomenorrhea), having 5 periods in 7 weeks?

Workup for Frequent Menstrual Cycles in a 20-Year-Old Female

The workup for a 20-year-old female with frequent menstrual cycles (5 periods in 7 weeks) should include evaluation for polymenorrhea, with laboratory testing for thyroid dysfunction, hyperandrogenism, and pregnancy, as these are common causes of menstrual irregularities in young women. 1, 2

Initial Assessment

• Definition of the problem: Having 5 periods in 7 weeks indicates polymenorrhea (cycles shorter than 21 days). This is abnormal, as the normal menstrual cycle ranges from 21-35 days 2
• Key history elements to obtain:
  • Pattern and duration of bleeding
  • Amount of bleeding (number of pads/tampons used)
  • Associated symptoms (pain, cramping)
  • Recent stressors, weight changes, or exercise habits
  • Sexual activity and contraceptive use
  • Medication history

Laboratory Workup

1. First-line laboratory tests:

   • Pregnancy test (to rule out pregnancy-related bleeding)
   • Complete blood count (to assess for anemia)
   • Thyroid function tests (TSH, free T4) - thyroid dysfunction is found in 13.6% of girls with menstrual disorders 3
   • Prolactin level

2. Second-line laboratory tests (based on clinical suspicion):

   • Hormonal panel:
     • Total testosterone and free testosterone (to evaluate for hyperandrogenism)
     • FSH, LH (to assess ovarian function)
     • Estradiol
   • Coagulation studies if heavy bleeding is present (PT, PTT, von Willebrand panel) 4
   • Pelvic ultrasound (to evaluate for structural abnormalities)

Common Causes to Consider

1. Anovulation/Ovulatory dysfunction: Most common cause of abnormal bleeding in adolescents 4
2. Thyroid disorders: Both hyper- and hypothyroidism can cause menstrual irregularities 3
3. Polycystic Ovary Syndrome (PCOS): Present in 22.6% of adolescents with menstrual disorders 3
4. Coagulopathies: Consider especially if heavy bleeding is present 4
5. Pregnancy complications: Always rule out in sexually active patients
6. Stress, excessive exercise, or weight changes: Can disrupt the hypothalamic-pituitary-ovarian axis

Management Approach

The management depends on the underlying cause:

1. For ovulatory dysfunction without other pathology:

   • Combined oral contraceptives (COCs) are first-line therapy for polymenorrhea 1
   • Start with monophasic pills containing 30-35 μg of ethinyl estradiol

2. For PCOS:

   • COCs or progestin-only contraceptives
   • Consider metformin if insulin resistance is present 1

3. For thyroid dysfunction:

   • Treat the underlying thyroid disorder

4. For bleeding disorders:

   • Hormonal therapy (preferably the 52-mg levonorgestrel IUD) 4
   • Hemostatic medications if needed

Important Considerations

• Menstrual irregularities should not be dismissed as normal variants; cycles >90 days apart are considered abnormal even in adolescents 2
• Early identification and treatment of menstrual disorders may prevent long-term health consequences, including reduced bone density from estrogen deficiency 2
• Untreated menstrual disorders can lead to anemia and reduced quality of life 4

Referral Indications

Consider referral to gynecology or adolescent medicine if:

• Heavy bleeding requiring transfusion
• Suspected bleeding disorder
• Failed first-line therapy
• Suspected structural abnormality
• Complex endocrine disorders

Remember that thorough evaluation of menstrual cycle disorders provides an opportunity for early diagnosis and treatment of conditions affecting the hypothalamic-pituitary-ovarian axis 2.