Eh, biasanya boleh both ways actually, ada orang keluar sekali je, ada yang beransur-ansur over a few days or even weeks sebelum labor. Mine keluar dalam chunks throughout the day, then masa contraction started baru tau dah nak deliver, so memang tak boleh predict sangat. If you're seeing discharge yang banyak or ada bleeding, better check with your doctor to make sure everything okay je, especially since setiap orang berbeza.