USG 4D

Bunda yg cantik2, klo usg 4D baiknya usia janin brp weeks ya? Trs menurut bunda penting gak sih USG 4D itu? (yg mau sharing thank you bgt, yg mau bully tolong ditahan, kasian baby diperut bunda nanti kena aura negative.. Salam respect each other ?)