Pregnancy and high blood pressure

The heart pumps blood into the blood vessels by alternately contracting and relaxing about 60 to 80 times per minute. This then creates pressure in the blood vessels. You will usually not feel whether your blood pressure is high or low, because this can only be determined with a blood pressure monitor. Blood pressure is checked extra often during pregnancy, because changes may occur during pregnancy. Blood pressure can become too low or too high.

How is blood pressure expressed in numbers?

Blood pressure is expressed in two numbers, where the first number represents the upper pressure, the pressure that arises when the heart contracts. The second number concerns the negative pressure and that is the pressure that is measured when the heart relaxes. Blood pressure is said to be normal when the upper pressure is less than 140 and the negative pressure is less than 80.

Pregnancy and blood pressure

In general, blood pressure decreases during pregnancy. This is caused by the fact that the changing hormones during pregnancy have a vasorelaxant and vasodilator effect. This creates less pressure in the vessels and lowers blood pressure. In 10 to 15% of women who are pregnant for the first time, their blood pressure rises too much and hypertension (high blood pressure) develops. This mainly occurs from the twentieth week of pregnancy.


When high blood pressure becomes very high, it is also referred to as pre-eclampsia, a severe form of gestational hypertension. In the past this was also referred to as pre-eclampsia. Pre-eclampsia is characterized by the fact that protein is found in the urine and this can often also be seen in the blood values during check-ups. If pre-eclampsia becomes very serious, eclampsia can even develop, causing convulsions.

Cause of high blood pressure

High blood pressure mainly occurs during the first pregnancy. If there is a slight increase, the next pregnancy will usually proceed without problems, but if there is a strong increase in blood pressure, the chance of an increase in blood pressure during a subsequent pregnancy will increase. It is not clear what causes the increase in blood pressure in most pregnant women.

Various diseases and conditions

With a number of diseases the risk of developing high blood pressure is increased, such as diabetes, kidney disease, pre-existing high blood pressure, as well as some autoimmune diseases.

Hereditary factors

Hereditary factors probably also play a role. Pregnant women who have a mother or sister who had severely elevated high blood pressure during pregnancy have a much greater chance of developing highly elevated blood pressure during pregnancy themselves.

Consequences of high blood pressure

For the pregnant woman herself, the danger of high blood pressure is that certain organs work less well. For the unborn child it may mean that its growth is delayed and that it is in less good condition. The severity of the consequences also depends on the degree of elevated blood pressure.

What can be done about it?

A salt-free diet used to be prescribed, but research has shown that this does not help. Nowadays, blood pressure lowering drugs are prescribed and if that does not help, a hospital admission usually follows.