Please see my comments to a writer a couple posts ago, and best wishes. Your best chance of having things work out is to get help early, before the consequences of addiction start to pile up. And as you know, they always pile up eventually.
I would NOT suggest you do this on your own without doctors supervision and direction!!! You CAN harm your baby by withdrawaing too quickly. Just because YOU don't have bad w/d symptoms doesn't mean your baby isn't suffering. Also, if you taper incorrectly you could actually miscarry. What's worse - lose the baby to death or tell the truth?
I also abused during my pregnancy with my daughter. I told my docs and they were great! It is not likely that you'll get CPS involved if you're honest with them and seek help! But if you don't tell them and get caught, that's another story. They would see that as not "complying" and not getting the help you need.
Just tell your doctor that you are an addict and THAT YOU WANT HELP AND SUPPORT to get and STAY clean. You should be fine from there on out as long as you follow directions from your doctors and do exactly what they tell you to do. That will greatly decrease your chances of having CPS involved.
Best of luck!