Ay, ito na talaga ang sign na malapit na! Based sa experience ko and ng iba sa circle ko, yung mucus plug usually comes out a few days or even weeks before labor, kaya hindi ka mag-aalala, it's actually your body's way of preparing for delivery, momshie! Since your OB said your cervix is soft na, sounds like you're progressing well na, so I'd just keep an eye out for other signs like contractions or more discharge and maybe message your OB about it para sure lang, lalo na since you're so close na sa 39 weeks. Stay hydrated and rest mabuti, mama, you're almost there!