“An average healthy blood pressure should measure between 110/70 mm Hg and 120/80 mm Hg, but these figures may vary widely in pregnancies,” says Assoc Prof Tan ​Lay Kok​, Senior Consultant at the Department of Obstetrics & Gynaecology​, Singapore General Hospital (SGH), a member of the SingHealth group.

If your blood pressur​e rises above 140/90 mm Hg, it means you have high blood pressure. This condition typically increases the risk for heart disease, kidney disease and stroke.

The good news is that in pregnant women, high blood pressure is often mild. “However, it can become severe and affect both mother and child adversely,” says Dr Tan.

There are different terms for high blood pressure, depending on the stage at which it occurs:

Before the 20th week of pregnancy, high blood pressure is called pre-existing high blood pressure. This can be due to primary hypertension (also known as essential high blood pressure) or secondary hypertension, where there is an underlying cause, such as kidney disease.

A high blood pressure reading before 20 weeks of pregnancy usually means that you probably developed high blood pressure even before you became pregnant. But it is not possible to know for sure until after your baby is born.

High blood pressure which occurs after the 20th week of pregnancy is called gestational high blood pressure. It is also known as pregnancy-induced high blood pressure.

When this happens, your doctor will recommend additional blood pressure checks. Your urine will also be tested for protein. If your blood pressure continues to rise further, there may be a need to control it with medicines, such as methyldopa or calcium channel blockers.

If you have gestational high blood pressure, your blood pressure should return to normal within six weeks of giving birth.

Having pre-existing or gestational high blood pressure puts you at a higher risk of developing pre-eclampsia during pregnancy.​

​Read on to find out more about pre-eclampsia and eclampsia.

Ref: S13