Aw, first baby mo, congrats! Honestly, the best time to prevent them is ngayon habang pregnant pa lang kaya I'd suggest getting a good stretch mark cream and serum, a few of us moms swear by Mama's Choice Stretchmark Cream & Stretchmark Serum kasi they're safe to use while pregnant and breastfeeding, at they really work if consistent ka sa pag-apply, especially on belly, chest, at thighs. Apply mo religiously every morning and night, and make sure you're hydrating din from the inside, drink lots of water! Some moms say adding bio-oil or regular moisturizer on top helps pa, but the Mama's Choice combo is honestly the game-changer na ginagamit ng maraming kaibigan ko.