Hypothalamic Amenorrhea, FSH and LH levels
To look at the serum levels of FSH and LH might be one aspect of diagnosing Hypothalamic Amenorrhea.
Hypothalamic Amenorrhea is when your body, more specific your Hypothalamus, is shutting down reproduction because it senses a state of stress. The stress is mostly due to intense exercise in combination with disordered eating patterns (counting and/or restricting calories, excluding food or food groups). Your body is not broken, it could produce the hormones required for reproduction if it wanted to, but in the current state is chooses not to. It does so to protect you, currently it is not safe for you to become pregnant. Once the times of famine and scarcity are over, it will resume ovulation, and thereby reproduction again.
Hypothalamic Amenorrhea can be diagnosed by looking at lifestyle factors. A blood analysis can also be used in combination. In someone suffering from Hypothalamic Amenorrhea, the female sex hormones will typically be low. Usually FSH and LH levels are used to diagnose Hypothalamic Amenorrhea:
Follicle Sstimulating Hormone (FSH) <10 mIU/ml
Luteinizing Hormone (LH) LH<10 mIU/ml
Estradiol (E2) <50 pg/ml
It can sometimes also be advisable to look at the LH to FSH ratio. For someone suffering from Hypothalamic Amenorrhea, this ratio is typically low (<1). In those suffering from PCOS, this ratio will be high (>2). This can be good to know in case your doctor is giving you a PCOS-diagnosis, allthough you suspect it is Hypothalamic Amenorrhea that is the cause behind your missing periods.