In fact, salt restriction will probably make her blood pressure increase, not decrease. It can be an early symptom of toxemia, but in the well-nourished woman, it seldom is. Your friend needs to be sure that her diet is indeed adequate for pregnancy. If not, she may be on the road to the very problems her doctor suspects. BlueRibbonBaby.org for the proper prenatal diet to prevent toxemia.
Salt is a vital nutrient.
No woman, expectant or otherwise, can live without it. Neither can the unborn baby, who receives sodium from his mother's blood stream, through the placenta. Sodium requirements vary widely depending on activity level, environmental conditions, personal health, and many more factors. Pregnancy is one condition where the body actually requires MORE salt in order to remain healthy. Each person has many finely tuned mechanisms that work in the body to preserve the appropriate concentration of sodium in the tissues and in the bloodstream.