Diagnostic Workup for Secondary Amenorrhea

Initial Assessment

The American College of Obstetricians and Gynecologists recommends performing a pregnancy test as the first step in evaluation, as pregnancy is the most common cause of missed menses 1, 2
Recent weight loss or low BMI can trigger functional hypothalamic amenorrhea (FHA) 3, 2
Excessive exercise patterns can contribute to FHA 3, 2
Psychological stress can be a factor in the development of FHA 3, 2
Caloric restriction or energy deficit can lead to FHA 3, 2

Measuring serum FSH and LH levels can help differentiate between hypothalamic-pituitary causes and ovarian causes 2, 4
A low/normal FSH and LH level suggests hypothalamic amenorrhea 4
An LH:FSH ratio >2 suggests polycystic ovary syndrome (PCOS) 4
Checking serum prolactin levels can help rule out hyperprolactinemia, which accounts for approximately 20% of secondary amenorrhea cases 2
Evaluating thyroid function with TSH measurement is essential in the diagnostic workup 2

Performing a pelvic ultrasound can help evaluate for polycystic ovarian morphology (PCOM) and uterine abnormalities 3, 4
PCOM is defined as ≥20 follicles of 2-9mm per ovary or ovarian volume >10ml 3, 4

Functional hypothalamic amenorrhea (FHA) is characterized by low/normal gonadotropins, negative progestin challenge, and identifiable stressors 3, 2
Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, oligo/anovulation, and often polycystic ovaries on ultrasound 2
FHA-PCOM is a special entity where patients have features of both FHA and PCOM, affecting approximately 40-47% of women with FHA 5, 2

Addressing underlying causes such as weight restoration, stress reduction, and decreased exercise intensity is essential in the management of FHA 3, 2
Considering hormone replacement therapy to prevent bone loss and other consequences of hypoestrogenism is recommended for FHA patients 2
For PCOS, considering cyclic progesterone to induce regular withdrawal bleeding and addressing metabolic risks with lifestyle modifications is crucial 2

Monitoring bone mineral density in patients with prolonged hypoestrogenic states is essential 2
Regular assessment of menstrual patterns to evaluate treatment response is necessary 2

Patients with FHA-PCOM may be misdiagnosed with PCOS as they fulfill Rotterdam criteria (amenorrhea and polycystic ovaries) 5
Differentiating between FHA-PCOM and PCOS based on the presence of typical FHA triggers, negative progestin challenge test, and lower LH levels is essential 5, 3, 2