I don't think any of them were pregnant but Jastine Diamond, Melissa Perez, Valentina Orellana-Peralta and Jamie Feith were all white women or girls shot dead by American police in the last few years. Perez and Feith were acting dangerously, Jastine Diamond and Valentina Orellana-Peralta were both completely innocent. There is a clear 'culture war' narrative in the way the deaths of people who are shot by police in the US are reported on. And dead white women don't fit into it, so they don't become so widely known.
The problem is that the police in the US genuinely fear for their lives on an ongoing basis. Last year alone 64 officers were shot to death and 56 were killed by vehicles. They are killed during traffic stops, domestic violence call outs, disturbance call outs, while making arrests. They are even routinely ambushed and taken by surprise. And those numbers, 120 deaths in a year, are just the shootings and accidents where they die. Many, many more are left with severe injuries. There is no doubt that racism is still a big issue and a major part of the problem. But there is so, so, so much more to it than all bastard cops being trigger happy with black people. And as long as people focus on one aspect of a much, much bigger issue, things will only get worse, not better.