At the age of 2 months, a nurse noticed that my DS has uneven hip creases. So we eventually, did a US scan which indicated that both hips are fine with the alpha angle 63 degrees (left) and 74 degrees (right). The femoral head coverage was 58% (left) and 65% (right)

Now as she grows up the legs length and knee height difference become more pronounced. This week at the 4-month check the nurse has also noticed that and we are doing another USS.

What Are other reasons for this condition if not hip dysplasia?