Daenerys was trying to bring Khal Drogo back to life, and she didn't understand clearly that it would cost her the life of her baby. Neither she nor Cersi sacrificed their children in pursuit of power.
Every time one of Cersei’s kids died — and her own machinations and poor decisions led to each one — Cersei doubled down on ruthless power mongering.
Your description of Dany’s surface plot makes George R. R. Martin a piss poor writer, which he most definitely isn’t.