Congrats on the ladies. All of the white stuff I see in the picture is perlite. There could be some salt build up that I don't see though. Salt build ups looks like a thin layer of white frost over the very top portions of the soil. If you do have salt build ups you can flush your soil with lots of water, cut down on fertilizing, and you can create small mounds/lines on top of which salt will form and then remove the salt. If you are just talking about those larger white dots, it's perlite that has floated up through your soil (it's very buoyant when dry), and you have nothing to worry about.
The white layer in this picture is salt - it's hard and brittle and cracks into small scales (up close, in this picture the clay heavy soil is also scaling up due to being dry). If in doubt put it in your mouth and it'll taste like salt