Hi mama! Honestly, I haven't tried barley juice myself during pregnancy kasi I was worried, but a few of my mum friends did drink barley water (plain lang) and they said it was okay, maraming sources say barley's generally fine since it's just grain. But the wheatgrass and mangosteen combo, I'm not 100% sure about together while pregnant, so I'd really recommend asking your OB first bago mag-start, especially since you're mixing three things at once. Better safe than sorry with pregnancy, diba? Let me know what your doctor says, curious rin ako!