This was not a smooth process. The rise of executive power sometimes hurt important interests and always rubbed against the republican sensibilities that Americans inherited from the founders. From time to time, Congress reaped political benefits from thwarting the president. But today Congress reacts rather than leads.
Some medical conditions can cause low blood pressure. These include: 1  Pregnancy. 2  Because a woman's circulatory system expands rapidly during pregnancy, blood pressure is likely to drop. 3  This is normal, and blood pressure usually returns to your pre-pregnancy level after you've given birth.
Blood pressure varies from one person to another. A drop as little as 20 mmHg, can cause problems for some people. There are different types and causes of low blood pressure. Severe hypotension can be caused by sudden loss of blood (shock), severe infection, heart attack, or severe allergic reaction (anaphylaxis).