Even slightly elevated blood pressure early in pregnancy a bad sign

Even a slight rise in blood pressure during pregnancy may spell trouble later on.
Even a slight rise in blood pressure during pregnancy may spell trouble later on.

Even a small increase in blood pressure during your first trimester could spell bigger trouble later in your pregnancy, new research suggests.

Those troubles can include gestational high blood pressure, which develops after the 20th week of pregnancy, and preeclampsia (high blood pressure and protein in the urine), the researchers explained.

Higher stroke risk

Both conditions increase the risk for stroke in an expectant mother and for stillbirth, preterm birth and low birth weight. Preeclampsia also increases the risk of life-threatening seizures in the mother (eclampsia).

In this study, the researchers analysed data from about 8 900 pregnant women in the United States. Of those who had elevated blood pressure in the first trimester (120/80 to 129/80 mm Hg), just over 30% developed a high blood pressure disorder of pregnancy. This was a 42% higher risk than among women with normal blood pressure (less than 120/80 mm Hg) in the first trimester.

Among women with stage 1 high blood pressure (130/80 to 139/89 mm Hg) in the first trimester, almost 38% developed a hypertensive disorder of pregnancy, which was an 80% higher risk than among those with normal blood pressure, the findings showed.

Stage 1 high blood pressure was associated with more than 2.5 times the risk for preeclampsia, according to the study.

An increase in blood pressure between the first and second trimester also increased the risk of a high blood pressure disorder of pregnancy, the investigators found.

Slight increases also dangerous

For example, among women with normal blood pressure in the first trimester, an increase in systolic pressure (the top number) between the first and second trimester was associated with a 41% higher risk of a high blood pressure disorder of pregnancy, compared to women with a decrease in systolic pressure.

An increase in diastolic pressure (the bottom number) between the first and second trimester was associated with a 23% higher risk of trouble during pregnancy, compared to women who had a decrease in diastolic pressure during that time.

The US National Institute of Child Health and Human Development-funded study was published in the American Journal of Obstetrics and Gynecology.

The findings suggest that blood pressure readings lower than those traditionally used to identify women as having high blood pressure may still be dangerous during pregnancy, study leader Dr Alisse Hauspurg, from the University of Pittsburgh School of Medicine, said in an institute news release.

Image credit: iStock

We live in a world where facts and fiction get blurred
In times of uncertainty you need journalism you can trust. For only R75 per month, you have access to a world of in-depth analyses, investigative journalism, top opinions and a range of features. Journalism strengthens democracy. Invest in the future today.
Subscribe to News24
Voting Booth
Have you entered our Health of the Nation survey?
Please select an option Oops! Something went wrong, please try again later.
Results
Yes
32% - 9435 votes
No
68% - 19997 votes
Vote