Pregnant women having high blood pressure (BP), or pre-eclampsia are at a higher risk of strokes and heart attacks than those having normal blood pressure, according to a recent study.
The study, presented at the British Cardiovascular Society Conference today in Manchester, found that if a woman had high BP during pregnancy their chances of developing a serious heart and circulatory related condition are increased by 45% and in women having a more serious pre-eclampsia this risk is increased by nearly 70%
Pre-eclampsia is a condition that occurs in, or soon after, pregnancy. Although it isn’t known exactly what causes pre-eclampsia, it’s thought to be caused by problems with the placenta. In cases of pre-eclampsia, the placenta doesn’t get enough blood from the mother’s body. This means blood flow between mother and baby is disrupted.
Pregnancy-related high blood pressure, or gestational hypertension, is high blood pressure that first starts when a woman is pregnant and usually goes away after they have had their baby. It can be mild (90-99/140-149), moderate (100-109/150-159) or severe (above 110/160).
The researchers studied about 6.5 million women in English hospitals between 1997-2015. This study covered nearly all (97%) of women who gave birth in England over the 18 years studies. 3% of the women studied had pre-eclampsia and 4% had high blood pressure when pregnant.
Key findings of the study include:
- Just over 276,000 pregnancies affected by high blood pressure and 223,715 with pre-eclampsia. This high number of people studied for nearly twenty years allowed them to look for the risks of more than 15 different kinds of heart and circulatory diseases, from a heart attack and stroke to heart failure and cardiomyopathy.
- The risk of developing a serious heart and circulatory condition increased by 45% if a woman had high blood pressure during pregnancy, or by nearly 70% for women who had experienced pre-eclampsia, compared to those who had normal blood pressure during pregnancy. For example, when just considering first pregnancies, 3 in every 1000 women who had normal blood pressure went on to develop heart and circulatory diseases after their pregnancy, while for women who had high blood pressure during pregnancy, it was 5 in every 1000, and 6 in 1000 for women who had pre-eclampsia.
- A history of high blood pressure during pregnancy raised the risk of having the most common form of stroke by 80% and doubled the risk of potentially fatal cardiomyopathies, a family of conditions where the heart muscle is diseased and becomes ineffective at pumping blood.
- A history of pre-eclampsia during pregnancy led to a three-fold increased risk in heart attacks and over double the risk of cardiomyopathy when compared to women with normal blood pressure during pregnancy.
- The more affected pregnancies that a woman had, the more her risk of serious heart and circulatory complications increased. For example, women with two or more pregnancies where they had high blood pressure were more than twice as likely to have a stroke than those with normal blood pressure.
- Those with two or more pregnancies with pre-eclampsia were nearly 4 times as likely to have the most common form of stroke and 3 times more likely to have a heart attack, compared to women with pregnancies with normal blood pressure.
Dr Clare Oliver-Williams, who carried out the research at the University of Cambridge, said:
“The women we studied had all recently had babies so they were younger than the average person who has a heart attack or stroke. So, although the number of cases of serious events like heart attack and stroke isn’t huge, there is an important increase.
“A pregnant woman can be busy worrying about lots of things – her due date, her work and maybe her other children, so it can be easy to put themselves last. But it’s important that all expectant mums to keep a close eye on their own heart and circulatory health, and it’s equally important that doctors recognize the symptoms of heart and circulatory diseases in women who have had complications during their pregnancies.”