Dr. Lesleann Hayward presented a fascinating case from clinic. A woman in her 40s presented with oligomenorrhea x4 years without weight loss, excessive exercise, galactorrhea, hirsutism, or menopausal sx. BMI, TSH, prolactin were normal. FSH was inappropriately normal with a very elevated estrogen level (like 2000s). Transvaginal US surprisingly didn't show any endometrial thickening but noted numerous ovarian cysts. Testosterone level was normal suggesting against PCOS. The patient's estrogen level continued to rise but normalized after stopping her biotin supplement and starting on low-dose OCPs. Though this case still leaves us puzzled, it was a great refresher on how to work up amenorrhea and oligomenorrhea in the clinic. When in doubt, no one will fault you for involving gynecology or endocrinology.
Let's refresh with some definitions:
Amenorrhea: lack of menses.
- primary: lack of menses by age 15 or age 13 is no breast development (usually an anatomic, genetic, or hormone deficiency an d not discussed here as not typically seen in adult world). If uterus is absent, get a karyotype to evaluate for Turners.
- secondary: absence of menses for >3 months in women who previously had a regular menstrual cycles OR absence of menses for > 6 months in woman with previously irregular menstrual cycles.
Oligomenorrhea: fewer than nine menstrual cycles per year or cycle length greater than 35 day
In thinking of possible pathology, it can be helpful to think of the hypopituitary axis and what can go wrong at each level.
However a more practical approach is to get standard amenorrhea labs and work through this algorithm for cause. (fun exercise to test your understanding of the hypothalamic-pituitary-ovarian axis!)
Let's order some labs:
The initial labs for someone with amenorrhea or oligomenorrhea is a beta-HCG (VERY important), prolactin, TSH, FSH, LH, estrogen (+ testosterone if hirsutism). Remember, low BMI, excessive exercise, and eating disorders can also cause amenorrhea so get a thorough history.