Adelaide University. Australia: Health researchers have been surprised by the results of a major
international study which shows that tightly controlling blood pressure
in pregnant women has no harmful effects for their babies. The
international study shows that, contrary to expectations, keeping blood
pressure in the normal range with medication does not affect a baby's
growth and development in the womb, and there are no differences in
outcomes for these babies at birth.
The study, led by BC Women's
Hospital and Health Centre and the University of British Columbia in
Canada, involved researchers at the University of Adelaide's Robinson Research Institute. The results have been published in the New England Journal of Medicine.
More than 980 pregnant women were involved in the study worldwide, including women from Adelaide.
"For
pregnant women whose blood pressure is too high, it places them and
their unborn babies at increased risk. The treatment of high blood
pressure during pregnancy is extremely important to help avoid
complications, such as stroke and death in the mother," says Professor Bill Hague from the University of Adelaide's Robinson Research Institute.
About
half of the participants received blood pressure treatment, usually
involving medication, to maintain tight control of their blood pressure
within strict limits, while the remainder of the women were allowed to
let their blood pressure rise a little, providing it was not to levels
that would be dangerous for the woman.
"It was originally thought
that blood pressure medication should only be used with caution in
pregnant women with high blood pressure, because it would have the
potential to impair placental blood flow, with negative impact on the
baby’s growth. However, we've been very happily surprised by these
results,” Professor Hague says.
"The women whose blood pressure
was maintained at normal levels reduced their chances of developing
severe high blood pressure, which is associated with an increased risk
of stroke and other major complications, and their babies were just as
happy and healthy as those whose mums were not on blood pressure
medication."
This is the first large high-quality study of its
kind looking at the potential impact of blood pressure control in
pregnant women with mild to moderate high blood pressure.
"The
results of this study have major consequences for the treatment of
pregnant women," Professor Hague says. "It helps to reinforce that it's
important to do research to get the right balance of what's good for the
mum and what’s good for the baby."
He says the message to
pregnant women with mild to moderate high blood pressure is: "Talk to
your doctor, follow their advice, but don't be afraid to continue with
blood pressure treatment because it offers the best benefits to both mum
and baby in the immediate term."
Further research is ongoing to see if there is any impact on the children as they develop in later life.