Pregnancy

If you have high blood pressure and are planning to have a baby or if you are already pregnant and have high blood pressure here
is information about prevention and treatment, along with antenatal care and pre-eclampsia.

What do I need to know if I already have high blood pressure and plan to become pregnant?

If you already have high blood pressure and you are planning to have a baby you should talk to your doctor about preparing to conceive. You can, like any other woman, have a successful and healthy pregnancy but you have a slightly greater chance of complications than other women do if you have high blood pressure. For this reason you will need to be more closely monitored than women without high blood pressure.

It is important to plan your pregnancy if you can

If at all possible your doctor will stop any medicines that you take for high blood pressure before you become pregnant. You should not become pregnant whilst you are taking atenolol (beta-blocker), ACE Inhibitors or Angiotensin Receptor Blockers as these medications can affect the development of your baby. Therefore it is important that you plan your pregnancy if you can.

Examples of ACE inhibitors and Angiotensin Receptor Blockers:-

ACE Inhibitors: Captopril, Cilazapril, Enalapril, Fosinopril, Lisinopril, Perindopril, Ramipril, Trandolapril

Angiotensin Receptor Blockers: Candesartan, Eprosartan, Irbesartan, Losartan, Telmisartan, Valsartan

However, some women will have to continue to take tablets for high blood pressure. If this is the case then you may find that your blood pressure falls in the middle of your pregnancy. If this happens, the tablets might be stopped. There are certain medicines that can safely be taken during pregnancy, so if you need to continue to take medications, there are choices available.

Throughout your pregnancy you will need to have your blood pressure checked regularly, at least once a month. Some women find it useful to buy a monitor to use at home, so that they can check their blood pressure levels in between the times when they see their doctor or midwife. Check with your midwife or doctor before you decide to buy a monitor, as home measurement may not be appropriate for everyone. Make sure that you use an accurate, properly validated machine. See the information about measuring your blood pressure, which explains how to take your blood pressure readings properly and identifies details of accurate blood pressure monitors to use at home

The Microlife 3BTO-A (2) is supplied with two different sized cuffs provided and is ideal for use during pregnancy and other validated machines with different cuff size are available from Medisave

5% or one in every twenty women will develop high blood pressure whilst they are pregnant. If your blood pressure rises by a small amount and your urine contains no protein, then this is called gestational hypertension. If your blood pressure rises by a large amount, and your urine contains protein then this is called pre-eclampsia. It is now thought that gestational hypertension may be a milder form of pre-eclampsia so careful monitoring is essential.

Pre-eclampsia is caused by a problem with the placenta, which joins mother and baby and supplies the baby with nutrients and oxygen from the mother’s blood. It is potentially very dangerous for both mother and baby if it is undetected. The signs and symptoms are a rise in blood pressure and protein in the urine. 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. It is very important that all pregnant women have regular checks by their midwife throughout their pregnancy, so that any problems can be spotted early and dealt with.

If you are found to have pre-eclampsia then you and your baby will be closely monitored. The only way to stop pre-eclampsia is for the baby to be delivered, which can sometimes mean a premature birth. Action on Pre-Eclampsia is an organisation that provides information on pre-eclampsia.

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, may ask you to take medications to lower it. There are medicines that are safe for you and your baby, but you will need to be monitored closely. Your doctor will avoid medications unless there is no alternative.

Methyldopa is the medicine most commonly used to manage high blood pressure during pregnancy. Diuretics, ACE inhibitors, Angiotensin Receptor Blockers and atenolol (a beta-blocker) should not be used during pregnancy. Other beta-blockers, such as labetolol are occasionally used, though there is very little evidence about their effects during pregnancy. Likewise, there is very little information on the use of calcium channel-blockers in pregnancy. If your blood pressure is sufficiently high, then these latter drugs will be used to reduce it.

If you develop high blood pressure during your pregnancy then it is very important that once the baby is born that you make sure your blood pressure is regularly checked until it returns to its usual level. 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 important to check that this has happened.

If I already have high blood pressure prior to becoming pregnant am I more likely to develop pre-eclampsia?

If you already have high blood pressure then you do have a slightly greater chance of developing pre-eclampsia in pregnancy. Your doctor and midwife will closely monitor your blood pressure and then decide to use treatment if it starts to rise.

There is no way of preventing pre-eclampsia, though you should eat a healthy diet (low in salt and saturated fats and high in fruit and vegetables) throughout your pregnancy, to ensure that you and
your baby are healthy.

What do I need to know if I had 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.

There has been some research which suggests that women who have high blood pressure or pre-eclampsia during pregnancy may be more likely to have a stroke or heart disease much later in life. 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 your blood pressure can be picked up and treated when necessary. If you have had pre-eclampsia or high blood pressure during a pregnancy, it is even more important that you have your blood pressure checked as you grow older, ideally every year.

Can I breast feed my baby if I am taking medicines for high blood pressure

There is some evidence that atenolol gets into breast milk, although this has affected the baby in just two cases. All other medicines for high blood pressure are safe in breast-feeding, but in general doctors are keen to avoid using medicines in women who breast-feeding. You should make sure that your GP knows if you intend to breast-feed.

Need to know more?

Your midwife, obstetrician or doctor can help with more information.
You may also find the following organisation useful:

APEC (Action on Pre-eclampsia)

84-88 Pinner Road

Harrow

Middlesex HA1 4HZ

Telephone: 020 8863 3271

References:

Article: Hypertensive diseases of pregnancy and risk of hypertension
and stroke in later life: results from cohort study

Publication: British Medical Journal, April 2003, Volume 326 Page
845

Authors: B Wilson, M Stuart Watson, G Prescott and others

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