My 1.5 month baby has normal shape but different size ears 4 mm different. i am so upset. why it happened. she passed hearing tests and healthy otherwise. ent said there is no concern but they are different size. do they get adjust when she grows?

The outer ears form from islands of cartilage and tissue and are easily recognized by 12 weeks but continue to grow/change into adulthood. They are subject to a variety of forces inside the womb that can compress/flatten/curl/distort the outer edges. Exactly equal size & shape is unusual. The cited difference does not suggest an internal or other disorder.