Screening Bowel Infection Echogenic Bowel At 24 Weeks Pregnancy?

Echogenic bowel at 24 weeks pregnancy? - screening bowel infection

After 24 weeks I was in my clinic, only because the weekend a few pink-times (Flow I thought it was bleeding). Up to 24 weeks, everything was perfect, all the results and it was all was in order, the NT test 1:4200.
So when the day of the exam on the same day I arrived at the hospital, they found the baby echogenic bowel. I was thrown the torch and cystic fibrosis, has been all negative.
Rescaned At 28 weeks, I again and then I do not see the echogenicity Bowell was more ...
What do you think it means?
I know I am not an amniocentesis, but I'm really scared of him ...
What are my chances of a child if an abnormal bowel echogenicity disappeared in 4 weeks and increased blood test results for infections were negative?
Is it really necessary to make, amniosentecis?