Uy mamsh, brown discharge after TVS (transvaginal ultrasound) is actually pretty common, a lot of us had that din, lalo na if it was a bit rough or if may slight irritation, pero since you have PCOS and you're preggy, mas better to message your OB agad para ma-check lang talaga and ma-rule out anything else, kasi peace of mind lang yan and they know your case best! Let me know how it goes ha, sending you baby dust!