The mother got pregnant either shortly before or right after the two "parents" killed Riley. (The father is the stepfather.)
From the timing, I'd say she got pregant almost immediately after they killed Riley, but it could have been a month or so earlier. I'd have to look at the timeline again.
They are not seeking the death penalty because it is harder to prove intent to kill with beating a child like this--I know, really sad, but the defense has a window to argue that the parent didn't realize how badly hurt the child was. Makes it easier to get a conviction overall if that isn't a point that the jury can get hung up on, and this is Galveston County, not Harris County/Houston area. Galveston is typically a lower income/harder jury for issues like this--the Galveston DA has been burned in the past on really obvious cases (like the one where the millionaire heir admitted he shot and cut up his neighbor, but he claimed self defense, and the defense had a window of excused because the DA couldn't prove that it WASN'T self defense--so Mr. Cut Up My Neighbor got a walk on a much lighter charge.
So the Galveston DA is playing it safe with the charges, but a lot of locals are not happy.
So far the father has NOT given up his parental rights. They had a family member all lined up to take the little baby boy, but his refusal botched that, so they are back to looking at extended family members again.
Baby Grace was one of the most heartbreaking crimes ever. I hope her mother lives in regret every single day of how she handed her child's life over to an insecure maniacal bully.