Most of us feel like we’re going to blow our top at some point in pregnancy, thanks to those raging hormones and overwhelming exhaustion.
But while your blood may be boiling over at the slightest thing, the fact is that most women actually have lower blood pressure than beforehand. This is because increased levels of progesterone relax the walls of your blood vessels.
However, for around 16 in 100 mums-to-be, high blood pressure can strike, especially in the third trimester as the greater volume of blood in your body needs to be pumped around, make your heart work even harder.
This condition is known as gestational hypertension. Your midwife will take your blood pressure at every appointment during your pregnancy to watch out for it, using the reading from your booking in appointment as a baseline.
What if I already had high blood pressure?
Expectant mums who have high blood pressure before they conceive, known as chronic hypertension, are at greater risk of suffering with it during pregnancy.
You really need to let your GP and midwife know as soon as you get pregnant (ideally before you start trying), especially if you are on medication for the condition.
Some drugs are not recommended in pregnancy so you may need to switch types. Blood pressure medications can also reduce blood flow to the placenta and your baby’s growth will need to be monitored. It may be that you can actually stop taking anti-hypertensive drugs in the first trimester if your blood pressure falls naturally.
Why can blood pressure go up in pregnancy?
Pregnancy can be a worrying and emotional time. There’s no proof that stress by itself causes long-term high blood pressure, but it can cause a temporary rise. This is sometimes called ‘white coat syndrome’ – the stress of a medic taking your blood pressure causes it to go up.
“I had high blood pressure at 16 weeks and the midwife put it down to too much stress,” says GPMummy55. “High blood pressure can sometimes be a blip and isn’t always a cause for concern.”
Being overweight or not very active can also increase your risk, as can smoking and alcohol.
Mums-to-be over 40 are more likely to get high blood pressure in pregnancy, although it can still affect young or healthy women.
“My blood pressure was high in both my pregnancies,” says Missy Moo. “Eventually my GP advised me to buy my own digital blood pressure monitor. I took my readings once a day and if there were any problems I told my GP.”
The good news is, for mums who only develop high blood pressure past the 20 week mark, it will most likely return to normal after you give birth.
The blood pressure readings look they gobbledygook! What do they mean?
Blood pressure is measured as two numbers, which show the pressure in your artery blood vessels. On paper it looks like a fraction – 145/85 mm Hg – while your midwife would say to you that your blood pressure is 145 over 85.
The top figure is the pressure when your heart contracts (systolic pressure), and the bottom is when it rests between heartbeats (diastolic pressure).
During pregnancy, these figures are a little different to the normal population. This means that:
Mild hypertension is blood pressure between 140/90 and 149/99 mm Hg.
Moderate hypertension is blood pressure between 150/100 and 159/109 mm Hg.
Severe hypertension is blood pressure of 160/110 mm Hg or higher.
Is high blood pressure dangerous for my baby?
Try not to worry because most of the time, high blood pressure in pregnancy is mild and harmless. Also, awareness of the condition is very good and your midwife will be looking out for it.
If your midwife or doctor think that there is cause for concern, you might be put on medication “At eight weeks pregnant I had high blood pressure so my GP put me on medication that was safe to take in pregnancy,” says Jokester.
“I took one a day and then went up to two a day after 20 weeks. It made me feel tired but I’m tired in pregnancy anyway! My blood pressure has gone down and so have my swollen ankles.”
But mine is through the roof – surely it’s dangerous?
Unfortunately, very high blood pressure can be a problem for you and your baby. It increases your chances of stroke, damage to your kidneys and liver, and there’s an increased risk of bleeding from your placenta.
Your baby might be at risk of being born prematurely and it can affect his growth. In severe cases, high blood pressure can cause stillbirth.
This is why your midwife and doctors will keep an extra close eye on you, and do all they can to keep it under control.
How can I lessen the risks?
You can help keep your blood pressure at a healthy level by staying active, so do gentle exercises like walking or swimming.
Eat a healthy balanced diet and cut back on salty and fatty foods. Cut back on sugar too – a recent study found that a sugary diet can raise your blood pressure as much as a salty one.
Take a good quality pregnancy supplement and cook with garlic, which is said to help high blood pressure.
When you need to worry…
Some cases of high blood pressure are caused by pre-eclampsia, a life-threatening condition which affects 3-5 per cent of pregnancies and can be very dangerous for both you and your baby.
It is widely screened for in pregnancy and as well as checking your blood pressure, your midwife will test your urine at each appointment for increased protein – another telltale sign of the condition.
However, every mum-to-be should be aware of the other symptoms of pre-eclampsia, particularly if you already have hypertension, if pre-eclampsia runs in your family, or if you’ve had it before.
Look out for swelling in the hands, feet and face, and painful headaches with flashing lights before your eyes. You may also vomit or have problems with your vision.
At 32 weeks pregnant, Ella was told she had high blood pressure and that she was in danger of getting pre-eclampsia. “I’ve been told I should put my feet up and rest a lot.”
I feel fine – do I need all these tests?
Sometimes there are no obvious symptoms with pre-eclampsia and you can feel perfectly well, which is why it’s so important to have regular antenatal appointments and make sure you don’t miss one.
If left untreated, it stops the placenta from working properly, which limits the supply of food and oxygen to your baby. It may also affect your own lungs, brain, liver, kidneys and blood clotting system. This may lead to fits (known as eclampsia), coma and even death.
If pre-eclampsia is treated both you and your baby will be fine and the condition should go away after the birth. In some cases, you will need to deliver early.
“I was put on two weeks bed rest because of high blood pressure,” says Penny. “My baby boy was delivered safely though so try not to worry. Take it easy and if you get any headaches or see flashing lights in your eyes call the hospital immediately because it could be pre-eclampsia developing.”