Rushali & Aashi

She wanted Ankita's child AFTER she realised that Pari could never be a Mom again. That the child was the only biological child Naren could ever have, also cos Pari-Naren's relationship had got strained after they lost their child. That is why she stole Ankita's child when she got the opportunity to do so, if the above two hadn't happened she would have never bothered about Naren's child or Ankita.

Priya's case was different. Very nicely it lay hidden almost till the end that Priya was Raunak's child. And when it finally came out, it came out in the open before everyone, so Rushali never really got a chance.

Plus I'm not sure if Rushali would have even wanted Priya anyway after the truth came out. She didn't want Mansi's child Ankita's sister and someone from the same chawl background she despised- both the sisters were responsible for sending Raunak to jail, and this child was a reminder of that incident. Rushali never had sympathy for Mansi so why would she have any love for that child. She would not have wanted that child till there came a situation where that child was the only hope for their family, maybe if she had come to know of Priya being Raunak's child rather than Ankita's whereabouts in Benaras, she would have stolen Priya rather than Ashi for Naren.

And.. the biggest point why she never bothered about Priya even when the truth came out- there was actually no way Rushali could EVER get that child. Raunak being a rapist, neither he nor his family would have any rights on Priya legally, and if she kidnapped him then everyone would have suspected Raunak-Rushali first and foremost as the truth came in front of everyone at the same time, all of them knew about it.