I'm pregnant i'm came positive for sma disease this is my second pregnancy my first child is healthy should i worried for that ?

SMA or spinal: muscular atrophy is a genetic disease affecting the part of the nervous system that controls voluntary muscle movement. SMA is an autosomal recessive disease. I presume you mean that you learned you are a carrier; we need to know the genetic status of your partner. If he is also a carrier, then each child has a 25% chance of having the disease; 75% healthy. The number of pregnancies has no effect.