Child Birth - Visa Application 176 - state sponsored

Hi,

We lodged our 176-State sponsored application in Oct, 2010. We haven't been asked for medical/PCC yet. I have only my wife as dependent in my application. Now, my wife is expecting baby and is gonna deliver it this month. I would like to know about the necessary documentation to inform CO about our baby. Can anyone of you please guide me what forms do I have to fill to inform CO/how to include our child in Visa application?

Thanks

Regards,

SKN