My baby’s arms measure 7 weeks behind and her legs 2 weeks behind?

Good afternoon,

I am a 39 year old woman and im currently pregnant at 30 weeks but my baby’s arms measure 7 weeks behind and her legs 2 weeks behind. Ive checked for down syndrome it came out negative other than that the baby is healthy everywhere. Does this specifically have to mean dwarfism??
Both her father and i are tall