Regina visits Rumpelstiltskin in prison
When the curse didn't work for Regina, she went to see Rumples in prison and he told her that the unborn child of Snow & Charming could break the curse. I don't know if Regina is aware that the child was a boy or girl. She may wonder about August.. he came to town for no reason that Regina is aware of.. whereas Emma was brought by Henry.
However, Regina may think the child died.. her guards told her that the child was 'gone' when they looked for her in the tree. Regina may not have thought that the child went to the same place as where the curse took them.. or that she'd ever be able to find them.
*edited to add: When Regina stormed into Snow & Charming's palace after the curse was enacted.. Regina did say, 'Where is she?!' (I am guessing she meant the baby, which I am guessing she intended to kill)... which would indicate that Regina was aware that Snow had given birth to a baby girl. How could she know this?? Either a spy in Snow & Charmings court.. or more likely, via the Genie and a reflective surface.
Edited by MorninStar, Apr 16, 2012 @ 2:44 PM.