New recommendations designed to help doctors assess, monitor, and manage high blood pressure during pregnancy were recently published by the National High Blood Pressure Education Program.

They urge doctors to differentiate between hypertension (blood pressure that is 140 over 90 or higher) and hypertension with protein in the urine, which signals that preeclampsia may be developing. Preeclampsia is a pregnancy-specific syndrome that affects the placenta, kidney, liver, and brain. It can develop gradually or appear suddenly, and it can range from mild to severe. About 1 in 4 women who already have hypertension will develop preeclampsia during pregnancy, usually during the middle trimester. Overall, hypertension occurs in 6-8% of pregnancies and can contribute to serious complications for both the mother and baby. Its causes remain unknown.

Hypertension and signs of organ dysfunction associated with preeclampsia typically disappear within 6 weeks of delivery. Women who developed preeclampsia early in their pregnancy or in more than one pregnancy are more likely to develop hypertension later in life.

The guidelines note that many patients with pre-existing hypertension may be able to control their blood pressure without medications or with less medication than they used before they became pregnant. If needed, however, most antihypertensive medications - except ACE inhibitors and angiotensin II receptor agonists - can be used safely during pregnancy.