Skeletal dysplasia..?

So I went to my doctor today and they saw from my ultrasound that my baby is just under the line on how normal his arms and legs are growing. He brought up that it was rare but he still mentioned skeletal dysplasia but I'm such a worrier I can't stop thinking about it. BABYS dad has short limbs, and he doesn't have SD but I'm still worried. Has anyone else experienced this? I need to ease my mind...