Differential Diagnosis for 3 Menses per Month with Scant Flow Since Birth in a 38-Year-Old Woman

Single Most Likely Diagnosis

• Uterine Anomalies (e.g., Uterus Didelphys, Bicornuate Uterus, or Septate Uterus): These congenital anomalies can lead to irregular menstrual cycles, including frequent menses, due to abnormalities in uterine structure and function. The scant flow could be related to the inefficient uterine cavity or cervical abnormalities associated with these conditions.

Other Likely Diagnoses

• Polycystic Ovary Syndrome (PCOS): Although PCOS typically presents with oligomenorrhea or amenorrhea, some women may experience frequent, light periods. The hormonal imbalance characteristic of PCOS could explain the irregular menstrual pattern.
• Thyroid Dysfunction: Both hyperthyroidism and hypothyroidism can cause menstrual irregularities, including more frequent periods with light flow. Thyroid disorders are common and can have a wide range of effects on the menstrual cycle.
• Pituitary Adenomas (e.g., Prolactinoma): These tumors can disrupt normal pituitary function, leading to hormonal imbalances that affect menstrual regularity and flow. Prolactinomas, in particular, can cause galactorrhea and menstrual disturbances.

Do Not Miss Diagnoses

• Endometrial Cancer or Hyperplasia: Although less common in younger women, endometrial cancer or hyperplasia can present with irregular, frequent bleeding. It's crucial to rule out these conditions due to their potential for severe consequences if left untreated.
• Bleeding Disorders (e.g., Von Willebrand Disease): These conditions can cause heavy or prolonged menstrual bleeding but might also present with frequent, light periods due to the body's attempt to compensate for the underlying coagulopathy.

Rare Diagnoses

• Androgen Insensitivity Syndrome (AIS): This rare genetic condition affects sexual development and can lead to irregular periods, though it's more commonly associated with primary amenorrhea.
• Congenital Adrenal Hyperplasia (CAH): Certain forms of CAH can cause hormonal imbalances that affect menstrual cycles, though this is relatively rare and often diagnosed in childhood.
• McKusick-Kaufman Syndrome: A rare genetic disorder that can include menstrual irregularities among its symptoms, though it's extremely uncommon and typically associated with other significant developmental anomalies.