Exercise and have a healthy diet. I get high blood pressure when pregnant (this is my second pregnancy) it just happens. I'm fit and healthy and continue this during pregnancy and have hardly any salt in my diet. Your doctor will monitor it any you go along :) I'm currently 33 weeks
Low sodium diet and workout
Avoid fast food and frozen food because they contain the most sodium. Prepare your own meal using sea salt or no salt. When you buy stuff at the grocery store look on the label to deep how many sodium it contains.
Avoid salt and stuff high in sodium