Tight Hypertension Control Deemed Safe in Pregnancy

The results of a new global study suggest that reducing elevated blood pressure during pregnancy is safe for the expectant mother and her child, countering the commonly held belief that tight hypertension control could impair fetal growth and cause worse health at birth.

That belief has led some health care providers, including lead author study Laura Magee, MD, FRCPC, MSc, FACP, to take a restrained approach toward blood-pressure-lowering medications in maternity.

“Before this study, I was a ‘less tight controller.’ I was hoping that this approach would be better for the baby, without increasing risks for the mother,” said Dr. Magee, a researcher at the Child & Family Research Institute and the University of British Columbia, in a press release. “However, I was wrong. Less tight control, which means allowing blood pressure to be mildly to moderately elevated in pregnancy, is not better for the baby. It’s actually harmful to the mother, who will more often experience levels of blood pressure that increase the risk of stroke. As a responsible maternity care provider, I can no longer justify a less tight approach to blood pressure control.”

Researchers tracked 987 women and their newborns at 94 sites across 15 countries. The women were between 14 and 33 weeks pregnant and were randomly assigned to either a less tight hypertension control group or a tight control group. Participants in the less tight control group had a target diastolic blood pressure of 100 mmHG, whereas the tight control group had a target diastolic blood pressure of 85 mmHG.

Most participants received blood pressure medication at some point during the trial.

There were no significant differences in pregnancy loss, admission to prolonged newborn intensive care, or overall maternal complications. Furthermore, less-tight control was associated with a significantly higher frequency of severe maternal hypertension, which can increase maternal stroke or death risk.

“For almost 50 years, there has been major controversy over whether it is safe or dangerous to use blood-pressure-lowering medications during pregnancy,” said Dr. Mark Brown, president of the International Society for the Study of Hypertension in Pregnancy, in a press release. “Following this well-conducted Control of Hypertension in Pregnancy study, which is 1 of a very small number of landmark studies in this field, we now have an answer: A lower level of blood pressure lessens the risk of stroke for hypertensive pregnant women without causing any new risk for baby. This will have a direct impact on the health of pregnant women worldwide.”