If I file divorce during my pregnancy what are my child's right

You can apply for mutual divorce in the family court. In mutual divorce a joint petition is prepared stating the facts when the marriage took place and from when the husband wife are living separately and similarly a brief reason in general that why they are not living together like differences etc.--no personal facts are disclosed.
on the date the first motion both husband and wife need to sign in court the joint petition and then get a six months future date and once they present and sign on second date the decree of divorce is granted.  Your child will not be an illegitimate as your child was consummated while you were married to your husband,