High blood pressure can sometimes be serious in pregnancy. You and your baby will need to be more closely monitored if you have high blood pressure.
Your midwife and GP will check your blood pressure at all your antenatal (pregnancy) appointments.
They will diagnose high blood pressure if you have 2 or more blood pressure readings of 140/90 or higher.
If you already have high blood pressure
High blood pressure before becoming pregnant is sometimes known as hypertension.
If you are pregnant and have a history of high blood pressure, you may be at higher risk of developing pre-eclampsia.
Urgent advice: Talk to your GP if:
you have a history of high blood pressure and either of the following:
- you are planning a pregnancy
- you think you may be pregnant
Some medicines that treat high blood pressure may not be safe to take when you're pregnant. They can reduce the blood flow to the placenta and your baby. They can also affect your baby in other ways.
If you are planning on trying to conceive, talk to your GP so they can switch your medicine.
If you find out you are pregnant, tell your GP immediately. They might want to change your medicine. They will advise you if you need to be seen sooner in the maternity hospital.
Do not stop taking your medicine suddenly - always speak with your GP or pharmacist.
If you develop high blood pressure during pregnancy
There are 2 types of high blood pressure that can develop during pregnancy:
You may not have any symptoms if you have high blood pressure during your pregnancy. This is why it is important to attend all of your antenatal care appointments.
If you develop high blood pressure for the first time while pregnant, you will need to be assessed more often in your maternity unit and by your GP. You and your baby will be more closely monitored.
It is likely you had high blood pressure before the pregnancy if it is found during the first 20 weeks of pregnancy.
Urgent advice: Contact your maternity unit, midwife or obstetrician urgently if you have:
- severe tummy pain
- bleeding from your vagina
Pregnancy-induced hypertension (gestational hypertension)
Pregnancy-induced hypertension is when your blood pressure rises during the pregnancy. This often happens during the third trimester, usually after 32 weeks.
Pregnancy-induced hypertension is also known as gestational hypertension.
If you develop pregnancy-induced hypertension, you and your baby will be monitored more closely. Obstetricians and midwives will plan the birth of your baby at a time that is safest for you and your baby. You may need to have your labour induced.
If you have pregnancy-induced hypertension, you may be at risk of a condition called pre-eclampsia. It is important to be aware of the signs and symptoms of pre-eclampsia.
Pre-eclampsia affects some pregnant people, usually from around 20 weeks of pregnancy. It can also affect some people in the first 6 weeks after their baby is born.
Most people with pre-eclampsia go on to have healthy babies. But if untreated, pre-eclampsia can be dangerous and even fatal for parents and for babies.
It is more common in:
- first time mothers
- older mothers
- multiple pregnancy
- fertility assisted pregnancy (egg donation and shared motherhood)
Learn more about pre-eclampsia
Complications of high blood pressure in pregnancy
High blood pressure during pregnancy can cause complications for you and your baby.
Problems for babies
High blood pressure can affect the way your placenta (afterbirth) develops. This might mean your baby does not grow as well as they should.
If you are diagnosed with high blood pressure your baby may need extra ultrasound scans. This is to check if they are healthy and growing well.
The scan will usually involve a Doppler scan. A Doppler scan measures how well the blood is moving through the umbilical cord.
In rare cases, high blood pressure can lead to the placenta separating from the inner wall of your womb. This is known as placental abruption. It causes you to have severe tummy pain and vaginal bleeding. This is dangerous for you and your baby.
Sometimes your baby will need to be born early to treat high blood pressure. This is known as premature birth or preterm birth.
If your baby is born early they are likely to need extra care after the birth, in a neonatal intensive care (NICU) or special care baby unit (SCBU).
High blood pressure after giving birth
If you had high blood pressure during pregnancy, it may continue for weeks after you give birth. Sometimes, it may be long term.
You will need to have follow-up check-ups with your doctors. Sometimes you will need to take medicine for several weeks.
In most cases, your GP will gradually reduce the dosage over 6 weeks.
Breastfeeding and blood pressure medicine
Breastfeeding is usually the healthiest choice for your baby, even if you are taking medicine. Talk to your GP or obstetrician before the birth. Some blood pressure medicines are safer to take than others when breastfeeding.