Hi mama! At 23 weeks, 580 grams ay actually on the heavier side, normal range is usually around 500-550 grams, so your baby is doing really well and growing nicely! But honestly, the most important thing is that baby's growth is consistent and on track with how baby's been growing week to week, kaya best talaga na i-monitor mo with your OB sa next ultrasound para makita nila ang growth pattern, sometimes bigger babies ay just healthy at normal lang for some pregnancies, walang dahilan to worry but your doctor can give you the most accurate picture. Congrats sa healthy pregnancy mo!