When you have high blood pressure, pregnancy requires special care. Here's what you need to know to take care of yourself and your baby.
If during pregnancy there were to be a bright red warning sign that flashed on one’s belly signalling potential danger – high blood pressure would be it! Not only can problems with blood pressure affect you, but your baby is also at risk of being born prematurely and having a low birth weight. But what exactly is high blood pressure and are there different types? What about treatment, prevention and care? Read on as we investigate further and answer these questions.
What is high blood pressure?
High blood pressure, also known as hypertension, means that the pressure of the blood in your arteries is too high. Blood pressure is recorded numerically, for example 140/85 mmHg. This is said as '140 over 85’ and is measured in millimetres of mercury (mmHg). The first number is the systolic pressure, which is the pressure in the arteries when the heart contracts. The second number is the diastolic pressure, referring to the pressure in the arteries when the heart rests between each heart beat.
- Mildly high blood pressure is 140/90 mmHg or above, but below 160/100 mmHg.
- Moderate to severe high blood pressure is 160/100 mmHg or above.
Why is high blood pressure a problem during pregnancy?
High blood pressure can decrease blood flow to the placenta, which can affect your baby's supply of oxygen and nutrients. This may slow your baby's growth and increase the risk of a premature delivery. High blood pressure also increases the risk of placental abruption, which is where the placenta prematurely separates from the uterus.
Did you know? 1 in every 20 women will develop high blood pressure whilst they are pregnant.
Different types of high blood pressure during pregnancy:
Sometimes high blood pressure is present before pregnancy. In other cases, high blood pressure develops during pregnancy. There are 3 main types:
- Chronic hypertension: If high blood pressure develops before 20 weeks of pregnancy or lasts for more than 12 weeks after delivery, it's known as chronic hypertension. This is commonly present, but not detected before pregnancy.
- Gestational hypertension: If high blood pressure develops after 20 weeks of pregnancy, it's known as gestational hypertension. Although it usually goes away after delivery, gestational hypertension may increase the risk of developing chronic high blood pressure in the future.
- Preeclampsia: Sometimes chronic hypertension or gestational hypertension leads to preeclampsia. This is a serious condition characterised by increased blood pressure and protein in the urine after 20 weeks of pregnancy. If diagnosed with this condition, you and your baby will be closely monitored. Sometimes the baby may be slow to grow and the mother may have swollen hands and feet, though there are other things that can cause these symptoms. The only way to stop preeclampsia is for the baby to be delivered, which can sometimes mean a premature birth.
High blood pressure during a previous pregnancy
High blood pressure in a previous pregnancy does not necessarily mean that you will have it again during further pregnancy, though you do have a slightly greater chance of having it than a woman who has never had a raised blood pressure. Many women who have high blood pressure during pregnancy have a normal blood pressure in later pregnancies. However, some research suggests that women who have high blood pressure or preeclampsia during pregnancy may be more likely to have a stroke or heart disease much later in life.
Treating high blood pressure during pregnancy
The good news is that high blood pressure can be treated during pregnancy. Your doctor may ask you to make some changes to your diet or change your lifestyle, and if your blood pressure is very high, you may need to take certain medications to lower it.
Diet: According to Lila Bruk, a registered dietician who specialises in woman’s health, various dietary changes can have a definite positive influence on high blood pressure during pregnancy. Although cutting down on one’s salt intake is the usual recommendation for lowering one’s blood pressure, it has been found that salt restriction does not have a significant effect on high blood pressure during pregnancy. Having said that, one should still avoid excessive salt consumption and should make sure that salt is either added during cooking or at the table – not both.
Increasing one’s calcium, magnesium and protein intake during pregnancy have been found to be an effective means of treating this condition. Taking in enough calcium has been shown to lower blood pressure during pregnancy. Calcium is found in dairy products (e.g. milk, yoghurt and cheese), as well as tofu and tinned salmon. Magnesium has been found to not only prevent, but also treat preeclampsia. Magnesium is found in dairy products, seeds, nuts, legumes (e.g. beans, chickpeas and lentils), wholegrain cereals (e.g. bran flakes) and dark green vegetables (e.g. spinach). An adequate protein intake is essential, as protein deficiency has also been linked to high blood pressure during pregnancy. Protein is found in meat, chicken, fish, eggs, dairy products and legumes.
Medication: If you are already taking medication to treat high blood pressure, then ideally, you should have this reviewed before you become pregnant as it may not be safe for use in pregnancy. Certain drugs, for example ACE inhibitors (medications that slow the activity of the angiotensin converting enzyme) are commonly used to treat high blood pressure. These can be harmful and should not be taken when you are pregnant. If you are taking one of these drugs then you are likely to be switched to another drug that does not interfere with foetal development.
Often medication to lower the blood pressure may be prescribed for a while until it is no longer necessary. This may, in certain cases, allow the pregnancy to progress further before delivery. If you have preeclampsia, magnesium sulphate may be given via a drip around the time the baby is delivered. The best time to induce the birth, or deliver by caesarean section, varies depending on individual circumstances however it is usually at least 2 weeks before the expected date of delivery.
Post-birth check-ups:
Blood pressure levels can rise sharply in the days following the delivery of a baby and can continue at high levels for a few weeks. In most women it returns to the same levels as prior to the pregnancy, but it is still necessary to check that this has happened by having your blood pressure closely monitored for at least the first 6 weeks following the birth.
Preventing high blood pressure during pregnancy
Taking good care of yourself is the best way to take care of your baby. Here are some simple steps you can take to prevent high blood pressure complications during pregnancy:
- Keep your antenatal appointments: Visit your doctor regularly throughout your pregnancy.
- Take your blood pressure medication as prescribed: Your doctor will prescribe the safest medication at the most appropriate dose.
- Get plenty of rest: Take a daily nap, if you can. Follow your doctor or a specialist dietician’s recommendations for exercise and activity. If you develop signs of preeclampsia, bed rest may be recommended.
- Eat healthy foods. Limit the amount of sodium and increase the amount of calcium, magnesium and protein in your diet. Also remember to take your prenatal vitamins.Monitor your weight. Gaining the right amount of weight supports your baby's growth and development, but gaining too much weight places additional stress on your heart.
- Know what's off-limits. Avoid smoking, alcohol and illicit drugs.
In Conclusion
It is important for everyone to know what their blood pressure is and to make sure that it is checked regularly so that any rise in blood pressure can be picked up and treated when necessary. If you have had preeclampsia or high blood pressure during a pregnancy, it is even more essential that you have your blood pressure checked as you grow older, ideally every year. Following a healthy lifestyle will certainly help to reduce your risk of developing complications during pregnancy, however sometimes extra preventative measures and medication may be required.
Sources and useful websites for more information:
