Blood pressure and pregnancy

All you need to know about how your blood pressure may be affected during pregnancy.

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Pregnancy health > Blood pressure and pregnancy

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You're likely to have your blood pressure taken regularly throughout your pregnancy - usually at every antenatal appointment you attend. We explain why keeping an eye on your blood pressure is so important while you're expecting.

A blood pressure reading is probably a procedure that you are already familiar with, where 2 readings are taken by inflating a cuff around your arm. These 2 readings represent the maximum pressure of your heart beating and the lowest pressure between beats, and will look something like 120/80.

What happens to my blood pressure during pregnancy?

Your blood pressure will generally go through several changes throughout your pregnancy, as your heart and body adjust to keep you and your growing baby well.

By your 6th month of pregnancy you will usually have produced about 2 and a half extra pints of blood, which your heart must pump around your body. The extra blood is needed to transport nourishment and oxygen to your baby through your placenta. Because of this, you may find that you start to feel much warmer as you approach the end of your 2nd trimester.

Around the middle of your pregnancy, your blood pressure will usually fall. This is because the hormone progesterone, which is produced during pregnancy, relaxes the walls of your blood vessels. The lower blood pressure may make you feel slightly faint or light-headed during this time.

Towards the end of your pregnancy, your blood pressure should return to normal.

What if my blood pressure rises during pregnancy?

This is only likely to be a concern to your doctor if your blood pressure rises above its normal amount, and stays consistently high over several readings.

This is why your blood pressure needs to be read at every ante-natal check-up - so that your doctor can get an overall impression of your blood pressure levels. A single high blood pressure reading would probably be disregarded if the rest of your readings show your blood pressure as being at a healthy level.

However if your blood pressure is seen to be consistently higher than usual, and a particular protein is found in your urine, your doctor may make a diagnosis of pre-eclampsia.

What is pre-eclampsia?

Pre-eclampsia is a condition that can run in families, but only affects about 10% of pregnancies. It is characterised by high blood pressure, swelling of the hands, ankles or face, and the presence of protein in the urine. If left untreated it could lead to a potentially serious condition called eclampsia, so it is very important to have your blood pressure checked regularly. This will ensure the health of both you and your baby.

What can I do to reduce the risk of pre-eclampsia?

If your blood pressure is prone to rising, the best thing you can do to try and keep it at a healthy level is to reduce stress. Try to get plenty of rest and relaxation.

Remember never to skip an ante-natal appointment, even if you feel fine and don't think you need to attend. If you cannot make an appointment, be sure to re-schedule it to a more convenient time for you.

Make sure that your blood pressure is checked at each of these appointments, and call your midwife if you feel at all unwell between appointments.

Finally, take whatever advice your doctor or midwife gives you, especially if your blood pressure does turn out to be high. Remember that you are protecting your baby as well as yourself, and by doing so you'll have a happy and healthy pregnancy.