Ohhh pregnancy yoga is so good, a few of us mums did it during pregnancy and swear it really helped with the back pain and breathing for labour! For Klang Valley, you can try searching Google Maps for "prenatal yoga near me" or "pregnancy yoga classes Klang", usually there's a few studios that offer specialized classes, or even some gyms like Gold's Gym have them. You could also ask your gynae if they have recommendations, or check Facebook groups for mums in the area since someone there usually knows the best instructors!