Oo naman, safe ang apple juice habang nagbrebeast, walang problema doon! Para sa kidney stones though, kailangan mo talaga ng mas maraming tubig at maybe some dietary changes, kaya better check with your doctor para sure kung ano exactly ang best approach for you while breastfeeding, lalo na kung may medication involved. A few of us moms have had similar issues and ang doctors namin always emphasized na hydration is key, hindi lang juice, but definitely worth asking your OB or a urology specialist para sa personalized advice.