Birth Control and High Blood Pressure
How birth control might increase your risk of high blood pressure
Why does a doctor check your blood pressure when you take the pill?
Depending on the kind of combined contraceptive pill you are using, taking the pill can actually increase your risk of getting high blood pressure (hypertension). Your doctor needs to check your blood pressure to make sure that it is staying at a safe level.
You are more likely to develop high blood pressure while on the pill if you:
- are overweight
- have a family history of hypertension
- had high blood pressure during pregnancy
If you smoke and take the pill you could also be at risk of high blood pressure.
Having a background history of high blood pressure which you may not be aware of can also increase your risk of blood clots and stroke. Hypertension is one of the main risk factors for heart attack and stroke, so your doctor will monitor your blood pressure and make sure that it remains at a safe level while you are taking the pill.
If you already have high blood pressure, speak to your doctor before taking the pill. Another form of contraception such as a progestogen-only pill or the contraceptive injection may be more suitable for you.
Should you check your blood pressure when you take the pill?
If you have high blood pressure and you want to start taking birth control pills, you should first see your doctor.
To make sure you take the right birth control for you, your doctor will first ask questions about your personal and family health to find out if you have other risk factors for heart (cardiovascular) disease. Your doctor will also want to measure your blood pressure to know how high it is. A blood pressure reading of over 140/90 mmHg is in the high threshold and taking birth control pills with this reading isn’t recommended.
You might still be able to use birth control pills, depending on if you have other risk factors. These might be: the results of your blood pressure checks, and how well controlled your blood pressure is. Your doctor may agree you can use birth control pills as long your blood pressure is checked regularly, or they may suggest you use another birth control method instead.
How can you get your blood pressure checked in Ireland?
You can get your blood pressure checked at your GP surgery by appointment. If you hold a medical card you won’t be charged. You can also get your blood pressure checked at selected pharmacies. You don’t normally need an appointment at a pharmacy, but you may be charged for the service. Apart from that it is possible to buy a blood pressure monitor and check it yourself at home.
Even if you have a high blood pressure reading at the doctor or pharmacy, you might have a normal reading at home, where you are more relaxed. The doctor or pharmacist may recommend that your blood pressure is monitored for 24 hours to find out if the reading is consistently high.
If this needs to be done, your doctor or pharmacist will fit you with a blood pressure monitoring device which includes placing a cuff around your arm that measures your blood pressure readings over a 24-hour period. 24-hour blood pressure monitoring is not covered by medical cards, so you will be charged for this service. Pharmacies will also charge you a fee for a 24-hour monitoring of your blood pressure.
What do the two numbers in a blood pressure reading mean and why are they important?
Blood pressure readings have 2 numbers, one on top of the other, for example 120/80 mmHg. The top number is your systolic blood pressure and the bottom one is your diastolic blood pressure.
- Systolic means the highest pressure when your heart beats as it pushes blood around your body.
- Diastolic means the lowest pressure as your heart relaxes between beats.
Even if only one of the numbers is higher or lower than it should be, this counts as either high blood pressure or low blood pressure. If your systolic number is consistently 140 or higher and/or your diastolic number is 90 or more then you may have high blood pressure. If your systolic number is consistently 90 or less and/or your diastolic number is 60 or less then you could have low blood pressure.
Many things can affect your blood pressure readings throughout the day, so a number of blood pressure readings need to be taken over a period of time to check if your levels are consistently high or low.
What does ‘high blood pressure’ mean?
High blood pressure (a reading of 140/90mmHg or higher for a number of weeks) means that a strain is being put on your arteries and major organs – the brain, heart and kidneys. This extra strain can increase your risk of future health problems including heart attacks, strokes, kidney disease and some forms of dementia.
Good to know: High blood pressure usually has no signs or symptoms, therefore the only way to find out if you have it is to get yours checked.
What can I do if I have 'high blood pressure'?
If you have consistently high blood pressure readings, there are things that you can do to bring your levels back down and reduce your risk of developing further health problems.
For example, these lifestyle changes can help to lower your blood pressure:
- Reduce your salt intake – eat more wholefoods and natural foods, avoid processed foods and adding extra salt to anything you cook from scratch.
- Eat more fruit and vegetables – aim for at least 5 portions of fruit and veg a day.
- Reduce your alcohol intake – drink in moderation, no more than 2 units per day (one unit is a small glass of wine or half a pint of cider or beer). Drinking more than this amount over time can slowly raise your blood pressure.
- Give up smoking – smoking has the effect of immediately raising your blood pressure and also causes your artery walls to narrow over time, further increasing your blood pressure.
- Lose weight – if you're overweight, eating a healthy balanced diet and taking regular moderate exercise helps you to lose weight and reduces your risk of high blood pressure.
If you're thinking of going on the pill and already have high blood pressure, speak to your doctor.
What does ‘low blood pressure’ mean?
Some people have naturally low blood pressure (hypotension). Low blood pressure means that you have a lower risk of heart disease or stroke, but if your levels are too low they can cause different health problems. A low blood pressure reading is a level of 90/60mmHg or lower. If either of the numbers is lower than it should be, this could mean low blood pressure.
What can I do if I have 'low blood pressure'?
Having low blood pressure is not usually a reason to worry. However, if your blood pressure drops too low it can make you feel dizzy and faint.
Speak to your doctor if you think that you might have low blood pressure. Most people with low blood pressure don’t need treatment, but if your doctor thinks that you would benefit from treatment, they will try to identify the cause of your low blood pressure and treat that first.
Dr Babak Ashrafi Clinical Lead for Service Expansion
Babak studied medicine at King’s College London and graduated in 2003, having also gained a bachelor’s degree in Physiology during his time there. He completed his general practice (GP) training in East London, where he worked for a number of years as a partner at a large inner-city GP practice. He completed the Royal College of GPs membership exam in 2007.Meet our doctors
Last reviewed: 09 Mar 2023