Can a patient's "natural" (drug-free) estrogen and progestrin levels be measured to target what's needed?

... meaning... can a clinician measure the "natural state" of a patient, gather what the patient's birth control goal is (duration of period, frequency, weight, other health details), AND then be able to somewhat accurately target what amounts of estrogen and progestrin levels are needed.... right down to even if the pills (yes, only considering pills here) should be monophasic, biphasic, triphasic... ??? Or would that be too expensive to do for a month/need to be done too many times a month/for several months... just isn't done? ...Or do clinicians just seem to pick what to prescribe with loose guidelines, see what happens, and go from there? seriously...

I mean... you can take blood tests for thyroid levels... why not female horomones? wouldn't that be more accurate? deal with the side effects afterwards if/as they come (moody, weight gain, whatever)?

Thank you for all you consideration and time

Unfortunately, the range of "normal" levels of estrogen varies widely enough that it is almost impossible to say whether a woman's levels are "abnormal" or not. The amount of progesterone varies by an immense amount between normal cycles and pregnancy, so again, the term "normal" has little meaning.

Although doses vary slightly between oral contraceptives, most fall into general categories that differ very little between them except for some side effects and idiosyncratic effects.

As such, there can be very little to guide a doctor to recommend one oral contraceptive over another. In fact, when it comes to effectiveness, they are all essentially identical--they are all more than 99% effective, regardless of what your "normal" hormone levels are.