Managing Blood Pressure While Pregnant

High blood pressure treatments during first trimester are safe

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Pregnant women who take high blood pressure medications in the first trimester are not putting their baby at risk of birth defects.  But not managing high blood pressure itself can increase many risks.

A type of medicine called ACE inhibitors are commonly prescribed to treat high blood pressure (hypertension) – as well as heart failure and diabetes-related complications.

The drugs have been shown to raise risk for birth defects in the second and third trimesters of pregnancy, but it was not clear whether it was safe to take the drugs in the first trimester. This latest study shows that taking ACE inhibitors in the first trimester is not dangerous.

"High blood pressure - not drugs - can harm your baby."

The study was conducted by the U.S. Department of Health and Human Services’ (HHS) Agency for Healthcare Research and Quality. Researchers looked at more than 465,000 women, all of whom had delivered a baby in the Kaiser Permanente Northern California healthcare system from 1995 to 2008.

In addition to tracking a mother’s use of ACE inhibitors, researchers also took into account the mother’s age, ethnicity, obesity, and the number of times she has given birth. The researchers decided to exclude women who had pre-existing diabetes and obesity so they could get a more accurate assessment of the link between ACE inhibitors and birth defects.

About 6-8% of pregnant women experience high blood pressure, 70% of which are first-time pregnancies, says the National Institutes of Health.

In the study, 1.6 out of every 1,000 mothers was taking ACE inhibitors, and 38 of every 1,000 women took other high blood pressure drugs.

High blood pressure can harm the mother’s kidneys and other organs, and can cause low birth weight and early delivery. It also increases the baby’s risk for congenital heart, brain or spinal cord defects.

Women should consult with their doctors and find the most effective way to manage their high blood pressure, especially if they’re pregnant, said Dr. Carolyn M. Clancy, director at AHRQ, in a press release.

The Food and Drug Administration advises women to stop taking ACE inhibitors - and switch to another drug - once they’re pregnant. The agency issued a black-box warning against taking the drugs in the second and third trimesters of pregnancy in 1992.

The study, published in BMJ, found that if birth defects occur, it is most likely due to the underlying high blood pressure.

Reviewed by: 
Review Date: 
October 21, 2011
Last Updated:
October 21, 2012