I delivered stillbirth during 24 week due to pressure..what are the preventive measure to take before next pregnancy?

Exercise: If by "pressure" you mean elevated blood pressure or preeclampsia, the best you can do is to get fit and exercise. Make sure you're at a healthy weight as well. You can check your bmi to see what that weight would be. Exercise, though, is the best way to bring blood pressure down. You may need medication? Talk with your md about that. Exercise is free and effects are long lasting!