Do I have to report this pregnancy and will it affect the decision of judge and worker to continue the reunification plan for me and my children?

Of course you maintain a right to privacy for yourself, but the decision on whether or not to tell your social worker should not be made lightly. First, be honest with your social worker. If she/he asks, then tell the truth. If they ask why you did not tell them immediately, look surprised and say something like "I was waiting until 22 weeks to make the announcement" (or something like that, unless you have already told friends and family). If part of your case plan for your other children involves domestic violence and you are supposed to have terminated the relationship with the abuser, being pregnant can imply that you have not done so. If domestic violence is not an issues in your prior CPS history then you are probably fine to tell the social worker.