If I were you, I would be scared... Sorry but when someone tells me they are under treatment but they don't know the tumor type, I feel, as a fellow pituitary patient, that your treatment is lacking, and you deserve to get another opinion.
Let me put it this way... I found my tumor, was told to ignore it and 12 years later my life was destroyed. My story is not typical but is not rare. I was not able to pinpoint my tumor type for about 11 years.
It may happen that pregnancy will bring about a hormone vacation in that the body tries very hard to protect the baby but it will be a high risk pregnancy. Are you under the care of a pituitary center and do you know the tumor type? Some more than others will be made active by pregancy.
Of course having a baby is a great thing! I just am concerned about tumor type. There may be risk of sheehan's syndrome or apoplexy.
You need another doctor. Your lesion is actually tending on the larger size for a pituitary lesion and you need to determine what type it is and your previous doctors have not done you well by not determining the type and getting you a treatment.
Size is relative in pituitary - 10mm is considered large and you are only 1mm away! Unless you know the type, pregnancy could be a risk as it could grow during the pregnancy and depending on where the tumor sits, it could create issues.
Please find a pituitary center and get copies of your tests.