High Blood Pressure In Pregnancy: What Does It Mean?

Midwife and FFHQ Pregnancy Expert, Avril Flynn, shares everything you need to know about high blood pressure in pregnancy.

As I’ve mentioned before, one of the checks that your midwife, or another healthcare professional, does at every single antenatal appointment is check your blood pressure.

The change to your circulation system in pregnancy is utterly fascinating. While your blood volume increases by 50%, your red blood cells increase by only a third (this is why some pregnant women might need to take iron supplements). 

Your entire circulation system works in unison with the baby's to provide your growing baby with life support- food, energy and oxygen. This is done automatically and without conscious thought on our part!

Our bodies are incredibly smart, and evolution has ensured that while we don’t know what we are doing when we are pregnant, we can trust that our bodies do - most of the time!

Pregnancy is a condition and not an illness.

I always say that pregnancy is a condition and not an illness.  However, being pregnant, and all of these massive changes do put your body under added stress and sometimes as a result, blood pressure can be an issue.

In early pregnancy, this can mean your blood pressure can be a bit low, but more commonly in later pregnancy, it can be a bit high. Women who are obese, inactive or have a family history, are more at risk.

A healthy diet, regular exercise and making sure you attend all your antenatal checks will help to reduce your risk.  High blood pressure, or hypertension, in pregnancy, can be separated roughly into 3 different types.

1. Chronic Hypertension

You might have a pre-existing high blood pressure issue that you have even outside of being pregnant. Sometimes you may be aware of this, other times you might not.

This is why the blood pressure checks you get at every appointment are so important. If high blood pressure is picked up in the first half of your pregnancy, or 20 weeks, it is usually of the chronic variety and can be controlled with medication. 

People with chronic hypertension (also called essential hypertension) picked up in pregnancy usually have to stay monitored and on their medication outside of being pregnant.

High Blood Pressure In Pregnancy: What Does It Mean?
When getting your blood pressure checked, it's important to take "white coat syndrome" into account.

2. Gestational Hypertension

Pregnancy-induced high blood pressure occurs after the 20th week in pregnancy and is more commonly diagnosed in the third trimester. Again, it can be controlled with medication and if well-controlled, it is usually not a big problem for you or your baby. 

It will have usually resolved itself by your 6 weeks check-up.  The symptoms of high blood pressure can include fatigue, headaches, vision changes, swelling or generally feeling unwell. 

3. Hypertension as a result of Pre-Eclampsia

One of the symptoms of this serious condition is high blood pressure. The other symptoms are oedema or swelling and protein in the urine. This is a rare but serious pregnancy complication and while the blood pressure can sometimes be controlled with medication, the disease itself can only be resolved with the delivery of the baby.

It can be a serious threat to both mum and baby but thankfully only seriously affects a small number of pregnant women. Why it happens and exactly how it happens are still not fully understood, but if a relative like your sister or mother has had it before, you have increased risk and will be carefully monitored.

It’s important to note that one high reading does not mean that you have anything wrong at all.

One important side note is a thing called “white coat syndrome”. Sometimes people (both pregnant and not) can get raised blood pressure when a doctor or nurse checks it, but when they wear a blood pressure monitor over a 24-hour period, it is found that they are totally normal.

It’s thought that the stress or worry of a medical person checking you is the thing that causes the blood pressure to spike. So, it’s important to note that one high reading does not mean that you have anything wrong at all.

If your doctor or midwife checks you, you won’t be diagnosed until you have several high readings, over several occasions.

If undiagnosed, high blood pressure in pregnancy can lead to very serious consequences for mother and baby.  Thankfully, as it’s checked at every visit you go to, it doesn’t often to lead to bad things happening. 

The take-home message as always is to try and lead a healthy-as-possible pregnancy, attend all your visits and if you have any symptoms or concerns, contact your midwife or doctor straight away.

For more information on high blood pressure in pregnancy:



Avril Flynn

Avril is a Registered Midwife, Childbirth Educator, Hypnobirth Practitioner, Podcast and Live Event presenter and mother of one.

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