Question 31

A 28 yo nulligravid woman stopped taking OCPs 1 year ago with the goal of pregnancy. However, she never resumed spontaneous menstrual cycles. Her PCP ordered tests showing FSH level of 45 mIU/mL, estradiol level of 12 pg/mL, TSH of 1.37 mIU/mL and prolactin of 9 ng/mL. The most appropriate next test to screen her evaluation is:

Answer Choices:

Bone density

Karyotype

FMR1 gene mutation

Antimullerian hormone

Antiovarian antibody

Correct Answer:

Karyotype

Explanation:

  • Primary ovarian insufficiency (premature ovarian failure) is diagnosed as ovarian failure before age 40 (happens in about 1%)

  • Usually involves amenorrhea though some women have occasional ovulatory cycles

  • Typically involves FSH > 30 mIU/mL

  • There can be exogenous causes (chemotherapy), autoimmune causes or genetic causes

  • Turner syndrome (45X) often presents as primary amenorrhea and has classic phenotype, but other structural abnormalities of the X chromosome can lead to primary ovarian insufficiency like Turner mosaic or Trisomy X

  • First step in women with primary ovarian insufficiency is to obtain a karyotype

  • If there is Turner syndrome, patient will need eval for serious sequelae like aortic rupture

  • If any portion of a Y chromosome is found, the patient is at risk of malignancy and should consider oophorectomy