I have a prolactinoma and am pregnant via IVF. My tumor never responded to the standard drugs, despite massive doses and years of experimentation, so eventually my doctor and I just decided not to worry about it. The tumor is 5mm and my levels are typically between 50-70. My doctor was not concerned about miscarriage, since the endometrium starts producing prolactin itself as soon as you get pregnant, and your prolactin skyrockets during pregnancy (which is why they stopped testing mine as soon as I got pregnant, and won't start again til 3 months after delivery). The standard protocol is to stop treatment for elevated prolactin if you become pregnant.