There are SO many reasons they ask this. they ask so you AND them can be aware of how long it has been, so you AND them can be aware and alert to the possibility of pregnancy. In case of POSSIBLE pregnancy, there are MANY medications and tests they cannot or should not use, or must use with different precautions. So, they do need to ascertain the possibility of a pregnancy, either one you know about or one you may not yet be aware of. ANd then they use that info to determine how to next proceed. If there is even the most remote possibility of pregnancy, there are different routes and paths they might take to provide you with whatever treatment etc you did come there for.
ALso some tests can have different results during different times during your cycle. So can some medications. ANd there are also some types of symptoms that might seem not at all related to your monthly cycle, but in the end could possibly be related to something hormonal or related to your cycle.
SO many women will say no, they are not pregnant, and they will say no there is no possibility of me being pregnant, and then lo and behold, guess what? They ARE preg.....or maybe have a tubal pregnancy--------or are having some preg related problem- or they are preg and do not know it yet, but refuse to acknowledge the possibility their method of birth control might have failed. Even if pregnancy and such per se have nothing at all to do with the reason you are there, in a fetus that is only say 1-2 weeks old ANY medications could pose potential harm, and NO doctor wants to take on the risk or responsibility for harming a fetus.
ANd yes, that is the number one question ANY doctor SHOULD ask EVERY female patient over the age of puberty. They really do need to determine if you are the only patient or if there is an unseen little patient hiding in there. They are protecting THAT patient.
