Ay, usually around week 6 onwards, pero honestly some of us moms noticed it earlier pa, like week 4 or 5, kaya very individual talaga! It's because ng hormonal changes during pregnancy, and as long as it's clear or milky white and walang smell or itching, totally normal lang and nothing to worry about, a few of us in our moms' group didn't realize ito na pala ang pregnancy sign namin until we tested positive na! Just wear cotton underwear para mas comfortable, and if it becomes yellowish, greenish, or may strong smell na, that's the time to call your OB. Congrats sa bun in the oven!