Hi, I Am 30 Week+4 Days And Today I Had

Hi, I am 30 week+4 days and today i had growth scan. The parameters on the baby were: HC = 279.8mm, AC=255.5mm, FL= 52.8mm, estimated weight 1377g, I have been told that they baby femur length is under 5 gentile for gestation and maybe she will have shorter limbs. Do you think this could be true? Is this dangerous? Could this be a sign of Down syndrome, although I had Harmony test and for all 3 chromosomal disorder I have been given result of 1/10,000, so low risk? Could this mean something else? Thanks,
Rositsa