But Magee, a clinical professor in UBC’s Department of Medicine and the Department of Obstetrics & Gynaecology, has up-ended her own beliefs with an international study published today in the New England Journal of Medicine.
The 15-country study shows that treating a woman’s elevated blood pressure during pregnancy is safer for her, and safe for her baby. As a result of these findings, Magee and her collaborators recommend normalizing blood pressure in pregnant women.
“Our trial showed that you should treat a mother’s high blood pressure in pregnancy,” said Magee, a physician at BC Women’s Hospital and Health Centre and a scientist at the Child & Family Research Institute. “This reduces her risk without increasing the risks for her baby.”
“Before this study, I was a ‘less tight’ controller,” says Dr. Magee, a specialist in women’s and maternal health. “I was hoping that this approach would be better for the baby, without increasing risks for the mother. 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.”
The study, which tracked the health of 987 women and their newborns at 94 sites in 15 countries, addresses an age-old belief that reducing elevated blood pressure during pregnancy might lead to reduced growth in the womb and impaired health at birth.
But normalizing a pregnant woman’s elevated blood pressure did not result in poorer outcomes for babies before or after birth. At the same time, allowing the mother’s blood pressure to be mildly to moderately elevated in pregnancy led to more episodes of dangerously elevated blood pressure that increase the risk of stroke and death for the mother during pregnancy.
“This will have a direct impact on the health of pregnant women worldwide,” said Mark Brown, president of the International Society for the Study of Hypertension in Pregnancy and a professor at the University of New South Wales.