Hypertension in Pregnancy
  • Hypertension is high blood pressure (BP), which is the force of blood against arterial blood vessel walls.
  • High blood pressure (BP) is usually 140/90 or higher, and severe high BP is 160/110 or higher. The top number (systolic) is arterial pressure during heart contraction, and the bottom number (diastolic) is arterial pressure when the heart is at rest.
  • In pregnancy, it is termed chronic if pre-existing or detected before 20 weeks.
  • Gestational hypertension is new-onset hypertension after 20 weeks without protein in urine.
  • Pre-eclampsia (PE) involves hypertension after 20 weeks with significant urine protein. (Tested by protein/creatinine ratio of 0.3 mg/dL or more or a dipstick reading of 2+; used only if other quantitative methods are not available).
  • In PE, there is systolic blood pressure of 140 mm Hg or higher or diastolic blood pressure of 90 mm Hg or higher on two occasions at least 4 hours apart.
  • In severe PE, systolic blood pressure is 160 mm Hg or higher or diastolic blood pressure is 110 mm Hg or higher.
  • PE can present with or without high BP, with serious other abnormal blood investigations and symptoms such as new severe headaches, upper belly pains, etc.
  • PE can affect many organs, including blood clotting, the brain, liver, kidneys, etc., without any protein in urine; Eclampsia involves severe PE with seizures.
  • Monitoring is crucial for effective management during pregnancy.
  • 1 in 10 pregnant women face high blood pressure.
  • 3 in 100 have pre-existing hypertension.
  • 4 to 8 in 100 experience gestational high blood pressure without progressing to pre-eclampsia.
  • 2 to 8 in 100 develop pre-eclampsia.
  • 16 in 100 with previous pre-eclampsia may experience it again in a future pregnancy.
  • Up to half of them might develop gestational hypertension in subsequent pregnancies.

For Mum:

  • High chance of a stroke.
  • Potential harm to kidneys and liver.
  • Higher risk of blood clotting problems.
  • High risk of serious bleeding from placental separation.
  • Possibility of seizures if eclampsia.

For Baby: Potential growth concerns for the baby.

  • Premature birth.
  • Risk of a stillborn child.

In most cases, there are no signs or symptoms of high BP. However, if you have severe high blood pressure, watch out for these red flag symptoms that signal a need for immediate hospital admission:

  • Intense, new headaches in the front and sides of your forehead.
  • Blurred vision, flashing lights, or spots in front of your eyes.
  • Belly pain, mainly in the upper part, just below the right ribcage.
  • New onset of vomiting after the 20th week of pregnancy.
  • Sudden swelling or puffiness of hands, face, or feet.
  • Breathlessness or feeling short of breath.
  • Perceiving reduced baby movements.
  • A general sense of not feeling well.

Antenatal management of chronic hypertension in pregnancy

If you had high blood pressure before pregnancy, our multidisciplinary team will assist you.

  • During the booking visit, we check medications, measure current blood pressure, test urine for protein, and assess your history focused on high blood pressure.
  • Baseline blood tests may be needed to monitor kidney and liver function affected by high blood pressure.
  • Most women with high blood pressure don’t have symptoms, but severe cases may show symptoms as discussed above.
  • Follow-ups are scheduled weekly or every 2 to 4 weeks based on blood pressure control.
  • After the 20th week, we monitor more closely for any signs of superimposed pre-eclampsia.
  • If this is suspected, we can offer a blood test (PLGF: placental growth factor) between 20 and 37 weeks of pregnancy.
  • Some blood pressure tablets, such as ACE inhibitors, ARBs, or thiazide-like diuretic tablets, are stopped within 2 days of your booking visit. This is to prevent potential harm to your baby. Alternative options will be discussed.
  • We will start you on Aspirin tablets, 150 mg once daily, from 12 weeks.
  • We will discuss alternate blood pressure treatment if your BP is 140/90 mmHg or higher.
  • We usually offer the medicines labetalol, nifedipine, or methyldopa in pregnancy.
  • The choice depends on any pre-existing treatment, their side-effects, benefits vs. risks (including effects on your growing baby), and any personal preference. We will discuss each Medicine in more detail if we need to.
  • Our goal is to maintain blood pressure at 135/85 mmHg or lower. If it falls below 110/70, we may recommend discontinuing tablets.
  • We will offer advice on weight management, exercise, healthy eating, and a low salt diet.

We recommend ultrasound scans at 28, 32, and 36 weeks to assess your baby’s growth. These scans include checking the amount of fluid around the baby and examining blood flow in the umbilical cord.

  • If your blood pressure is consistently below 160/110, with or without tablets, we can continue with the pregnancy until 37 weeks.
  • Beyond 37 weeks, birth options will be discussed based on individual circumstances.
  • Planning a Caesarean section before 39 completed weeks may involve offering mum steroid injections for the baby’s lung maturity. This will be needed for any planned childbirth before 37 weeks.
  • If childbirth is anticipated before 34 weeks, Magnesium Sulphate injections might be considered for the baby’s brain maturity.
  • Detailed discussions will precede any decision, and arrangements will be made to consult with a baby doctor if an earlier-than-normal delivery is deemed necessary.
  • The mode of birth is also open to discussion. There is no reason why you cannot have a natural birth unless there are other reasons.

After giving birth, we may measure your blood pressure:

  • Daily for the first 2 days.
  • At least once between day 3 and day 5.
  • As needed if there are changes to your blood pressure treatment.
  • Please continue your blood pressure medications and schedule a review appointment in two weeks. Our goal is to maintain blood pressure below 140/90, ideally 130/80.
  • If you were on Methyldopa during pregnancy, we will need to stop it within 48 hours of birth and provide an alternative. Details will be discussed with you.
  • A follow-up appointment is necessary six weeks after your baby’s birth. Kindly arrange an appointment accordingly.

Antenatal care with gestational hypertension:

If you have gestational hypertension, you will need extra monitoring to check you are not developing pre-eclampsia. This is more during:

  • First pregnancy.
  • Mum 40 years or older.
  • Pregnancy interval of more than 10 years.
  • Family history of pre-eclampsia.
  • Multiple pregnancies, such as twins or triplets or higher.
  • BMI of 35 kg/m or more.
  • Late booking.
  • Previous history of pre-eclampsia or gestational hypertension.
  • Pre-existing vascular disease.
  • Pre-existing or new diabetes in pregnancy.
  • Pre-existing kidney disease.
  • Autoimmune diseases such as SLE or antiphospholipid antibody syndrome. (Autoimmune disease is when your immune system, which normally protects you from infections, mistakenly attacks your own body’s cells and tissues).
  • Assisted reproduction pregnancy as IVF pregnancy.
  • Sleep apnea (where breathing temporarily stops when you are asleep).

Antenatal appointment schedule with gestational hypertension:

There needs to be a booking visit and then weekly follow-ups after detecting high blood pressure.

BP between 140/90 to 159/109:

  • We will offer BP tablets to maintain it at around 135/85 or lower.
  • We offer weekly BP and urine checks and special blood tests for liver and kidney function at booking and weekly.
  • PLGF test if offered once between 20 weeks and 37 weeks. This test checks the pregnant person’s blood for a protein called Placental Growth Factor, to assess the risk of pre-eclampsia.
  • We further suggest ultrasound scans for the baby, every two weeks.

Severe BP (160/110 or more):

  • We suggest admission to a hospital high dependency unit on a labor ward.
  • Mum will receive blood pressure medication via drip.
  • There will be frequent BP monitoring, to prevent risks to mum and the baby.
  • Blood tests, PLGF tests, and monitoring of the baby by CTG and ultrasound scans may be needed.

Timing of birth and postnatal management of gestational hypertension:

Similar to chronic hypertension.

What happens post-childbirth with gestational hypertension:

Similar to chronic hypertension.

  • If BP is 150/100 mmHg or higher and mum was not on medications antenatally, we may consider starting medication post-childbirth. Discussion will be done.

Antenatal care with PE:

  • We see mum in clinic every week to check their overall wellbeing, measure blood pressure, and test urine for protein.
  • We may need to do baseline blood tests to check blood clotting, kidney function, and liver function tests and an ECG.
  • We may need to start mum on Aspirin, Folic acid, Vitamin D, and Calcium if required.

We do ultrasound scans every two weeks to make sure the baby is doing well.

Hospital admission may be advised if:

  • Systolic blood pressure is 160 mmHg or higher, persistently.
    • Blood investigations show abnormalities, such as a significant rise in creatinine (a chemical released from muscles, and blood levels indicate kidney function) (90 micromol/litre or more), a rise in alanine transaminase (an enzyme released from the liver) (over 70 IU/litre), or a fall in platelet count (under 150,000/microliter). Platelets are tiny blood cell fragments that help to form clots to seal wounds.
    • Signs of eclampsia or impending eclampsia as fits, vomiting, headaches, blurring of vision, abdominal pain, and others are described.
    • Signs of any abnormal buildup of fluid in the lungs are noticed can make it harder to breathe.

We use a tool called fullPIERS to help us decide the best place for your care.

Treatment of PE in pregnancy:

  • If your blood pressure is between 140/90 and 159/109 mmHg and we have concerns or the risk prediction indicates high risk, we might admit you to the hospital for better care.
  • We provide treatment if your blood pressure remains at or above 140/90, starting with a medication called labetalol.
  • If labetalol is not suitable, we may consider other options as nifedipine. Methyldopa is offered if neither of the first options works well.
  • Our choice depends on factors like your previous treatment, potential side effects, risks (including effects on the baby), and your personal preferences.
  • We aim to keep your blood pressure at 135/85 mmHg or lower. We regularly monitor your blood pressure, conduct urine tests as needed, perform blood tests twice a week, and schedule ultrasound scans for the baby every two weeks.
  • If your blood pressure goes over 160/110, we suggest admission to the hospital for more intensive care, treatment, and closer monitoring with frequent tests.

Sometimes, we might need to plan for the baby to be born before 37 weeks. We will discuss this with you, your partner, and/or family if required.

It could be necessary if:

  • We cannot control blood pressure with three or more types of blood pressure medication.
    • Oxygen saturation levels in mums blood are consistently low (90% or lower).
    • Tests show problems with liver, kidneys, or blood clotting, or if there are any neurological symptoms like persistent headaches, vision problems, or seizures.
    • There is a risk of placental abruption (early separation of placenta with serious bleeding in the womb) or concerning findings in tests monitoring the baby’s well-being.

After we decide on a date for the baby’s birth:

  • In situations where birth is necessary, we will involve a multidisciplinary team including a baby doctor and an anesthetist.
    • If we plan for the birth to happen at or before 34 weeks, we will offer you a drug called Magnesium sulfate through a drip in your arm and a course of corticosteroid injections to help mature the baby’s brain and lungs.
    • Between 34 weeks and 36+6 weeks, we offer steroids only if a birth is planned.
    • From 37 to 38+6 weeks, we offer steroids if a cesarean birth is planned.

During childbirth in mums with PE:

  • Blood pressure will be measured regularly.
  • Antenatal BP treatment may continue.
  • At times, you might need treatment through injections directly into your veins.
  • Blood tests might be checked frequently.
  • Epidural is an option, and we will manage fluid intake carefully.
  • Assisted birth may be considered in the 2nd stage if severe high blood pressure does not respond to treatment.

  • At least 4 times a day in the hospital.
  • At least once between day 3 and day 5 after birth.

On alternate days until your blood pressure returns to normal if it was abnormal on days 3 to 5.

  • For those who took antihypertensive treatment during pregnancy, we will measure blood pressure:
  • At least 4 times a day in the hospital.

Every 1 to 2 days for up to 2 weeks after moving to home care until treatment stops and blood pressure is normal. We can teach you to self-monitor BP if needed and a list of people to contact if you need to.

If you had pre-eclampsia and did not take blood pressure medication in pregnancy, we may need to start treatment if your blood pressure is 150/100 mmHg or higher, after childbirth.

We will discuss if you have any other symptoms as severe headaches or upper belly pain, each time we measure your blood pressure.

We may continue BP treatment after childbirth and discuss breastfeeding. If blood pressure falls below 140/90 mmHg, we might reduce the doses. More so if this is below 130/80 mmHg.

For those who took Methyldopa before childbirth, we will stop it within 2 days after birth and may offer Enalapril for high BP after childbirth, with proper monitoring.

Postnatal hypertension treatment for women of black African or Caribbean family origin may include nifedipine or amlodipine. If needed, a combination of nifedipine (or amlodipine) and enalapril might be considered, with adjustments if necessary.

Sometimes we may need to add or replace any Medicine with Atenolol or Labetalol.

We aim to use the least number of tablets needed to properly control your BP. We will use once-daily medications when possible. We will repeat blood tests 48 to 72 hours after birth, and depending on results, further testing may be necessary.

We will monitor babies, especially preterm ones, for potential effects of BP tablets transferred through breast milk.

Mum may be discharged if there are no pre-eclampsia symptoms, your blood pressure is 150/100 mmHg or less, and blood test results are stable or improving. We’ll provide a plan for follow-up care and medication adjustments, with a follow-up in 2 weeks.

  • Mums urine will be retested for protein at the 6-week check, and if abnormal, referral to a kidney specialist may be considered.

This is a medical emergency.

  • 40% can happen in the postnatal period.
  • We will need to admit you to a critical care unit. You will need drugs to control your seizures and hypertension.

We may need to deliver the baby early. We will discuss all plans with you.

Recurrence of hypertensive disorders of pregnancy:

The overall risk of recurring hypertensive disorders of pregnancy is approximately 1 in 5 in future pregnancies. Specific risks based on the type of hypertension are as follows:

The chance of another PE in a future pregnancy rise if:

  • There has been any past or current any hypertension: About 14% (1 in 7 women).
    • Any past or current preeclampsia (PE): Up to approximately 16% (1 in 6 women).
    • There has been any past or current gestational hypertension: About 7% (1 in 14 women).

The chance of another gestational hypertension in a future pregnancy increase if:

  • There has been any past or current hypertension: Approximately 9% (1 in 11 women)
    • There has been any past or current PE: Between approximately 6 and 12% (up to 1 in 8 women)
    • There has been any past or current gestational hypertension: approximately 11% and 15% (up to 1 in 7 women)

The chance of chronic hypertension risk in a future pregnancy increase, if:

  • There has been any past or current PE. Approximately 2% (up to 1 in 50 women)

There has been any past or current gestational hypertension: Approximately 3% (up to 1 in 34 women)

Hypertensive disorders during pregnancy are associated with an increased risk of hypertension and cardiovascular disease later in life.

Lifestyle changes, including smoking cessation, a healthy diet, regular exercise, and maintaining a BMI between 18.5 to 24.9 kg/m², can help mitigate these risks.

For women who have experienced pre-eclampsia or hypertension with early birth before 34 weeks, pre-pregnancy counseling is offered to discuss potential risks and strategies for risk reduction.

  • The likelihood of recurrence increases with an inter-pregnancy interval greater than 10 years.
  1. Action on Pre-eclampsia. Available at: www.action-on-pre-eclampsia.org.uk. Helpline: 01386 761 848. [Accessed 6 April 2024].

  2. Stock SJ, Thomson AJ, Papworth S; the Royal College of Obstetricians, Gynaecologists. Antenatal corticosteroids to reduce neonatal morbidity and mortality. BJOG 2022; 129: e35–e60. DOI: 10.1111/1471-0528.17027. [Accessed 6 April 2024].

  3. NHS Choices. Keeping fit and healthy after childbirth. Available at: https://www.nhs.uk/conditions/pregnancy-and-baby/keeping-fit-and-healthy/. [Accessed 6 April 2024].

  4. NICE Guideline. Hypertension in Pregnancy. Available at: https://www.nice.org.uk/guidance/qs35. [Accessed 6 April 2024].

  5. Patient.info. High Blood Pressure in Pregnancy. Last updated by Dr Hayley Willacy, Peer reviewed by Dr Colin Tidy. Last updated 28 Apr 2020. Available at: https://patient.info/pregnancy/pregnancy-complications/high-blood-pressure-in-pregnancy. [Accessed 6 April 2024].

  6. ACOG. Preeclampsia and high blood pressure during pregnancy (FAQ 034 April 2023). Available at: https://www.acog.org/womens-health/faqs/preeclampsia-and-high-blood-pressure-during-pregnancy. [Accessed 6 April 2024].

  7. NHS. High blood pressure and hypertension during pregnancy. May 2021. Available at: https://www.nhs.uk/pregnancy/related-conditions/complications/high-blood-pressure/. [Accessed 6 April 2024].

  8. RCOG. Pre eclampsia (2012). Available at: https://www.rcog.org.uk/for-the-public/browse-our-patient-information/pre-eclampsia/. [Accessed 6 April 2024].

  9. Brown MA, et al. Hypertensive Disorders of Pregnancy. ISSHP Classification, Diagnosis and Management Recommendation for International Practice. Hypertension 2018; 72(1): 24-43. Available at: https://www.ahajournals.org/doi/10.1161/HYPERTENSIONAHA.117.10803. [Accessed 6 April 2024].

  10. Hofmeyr GF, et al. Calcium supplementation commencing before or early in pregnancy, for preventing hypertensive disorders of pregnancy. Cochrane Database of Systematic Reviews 2019. Available at: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD011192.pub3/full. [Accessed 6 April 2024].

  11. Khedagi AM, Bello NA. Hypertensive Disorders of Pregnancy. Cardiology Clinics 2020; 39(1): 77-90. Available at: https://www.clinicalkey.com/#!/content/journal/1-s2.0-S0733865120300825. [Accessed 6 April 2024].

  12. Knight M, et al. Saving Lives, Improving Mothers Care. MBRRACE-UK 2019. Available at: https://www.npeu.ox.ac.uk/assets/downloads/mbrrace-uk/reports/MBRRACE-UK%20Maternal%20Report%202019%20-%20WEB%20VERSION.pdf. [Accessed 6 April 2024].

  13. University of British Columbia. fullPIERS. Available at: https://pre-empt.obgyn.ubc.ca/home-page/past-projects/fullpiers/. [Accessed 6 April 2024].