High Blood Pressure and Pregnancy

There are three distinct types of high blood pressure that can complicate pregnancy. One type, not pregnancy-related, is called chronic hypertension and has minimal impact on a pregnancy when well controlled. The other type, called pregnancy-induced hypertension (PIH), is much more dangerous. The third type, chronic hypertension and PIH combined, is the worst of them all.

Chronic Hypertension

High blood pressure is famous for banging up blood vessels and the organs they supply. The hypertensive patient, feeling fine for years, may ultimately see this damage as strokes in the brain, heart attacks, and kidney damage. Strokes and heart attacks are serious enough, but damage to the kidney can further encourage hypertension (the kidneys play an important role in managing normal blood pressure in healthy people).

Substances called angiotensins are part of a cascade of chemistry in the kidneys. They are important in raising blood pressure. In healthy conditions, these angiotensins work to maintain normal levels of blood pressure. This is why the newer drug types to treat hypertension actually block the chemical reactions the angiotensins take part in. They are called ACE inhibitors ("Angiotensin-1 Converting Enzyme" inhibitors), and they include captopril and the brand name Vasotec (enatapril).

But—and this is a very important qualifier—these popular medications are suspected of causing deformities to babies, specifically if given in the later trimesters. Pregnant patients with high blood pressure must make do with older treatments. Fortunately, there are many of them, and they still all work fairly well. Among them:

• Lopressor (metoprolol) and labetalol: These two medications work by blocking the nerves that constrict the muscles in arteries and strengthen the heart's contraction efforts (resulting in lower blood pressure).
• Aldomet (methyldopa): This medication works in a similar way to lopressor and labetalol but is less selective in the particular nerve effects. As a result, there may be more side effects.