Hypertension in Pregnancy

Introduction

• Hypertension in pregnancy in usually defined as systolic > 140 mmHg or diastolic > 90 mmHg
• Or an increase above booking readings of > 30 mmHg systolic or > 15 mmHg diastolic

After establishing that the patient is hypertensive they should be categorised into one of the following groups

• Pre-existing hypertension
  • A history of hypertension before pregnancy or an elevated blood pressure > 140/90 mmHg before 20 weeks gestation
  • No proteinuria, no oedema
  • Occurs in 3-5% of pregnancies and is more common in older women
• Pregnancy-induced hypertension (PIH, also known as gestational hypertension)
  • Hypertension (as defined above) occurring in the second half of pregnancy (i.e. after 20 weeks)
  • No proteinuria, no oedema
  • Occurs in around 5-7% of pregnancies
  • Resolves following birth (typically after one month). Women with PIH are at increased risk of future pre-eclampsia or hypertension later in life
• Pre-eclampsia
  • Pregnancy-induced hypertension in association with proteinuria (> 0.3g / 24 hours)
  • Oedema may occur but is now less commonly used as a criteria
  • Occurs in around 5% of pregnancies

Symptoms of pre-eclampsia: Advise pregnant women to see a healthcare professional immediately if they experience symptoms of pre-eclampsia. Symptoms include:

• Severe headache
• Problems with vision, such as blurring or flashing before the eyes
• Severe pain just below the ribs
• Vomiting
• Sudden swelling of the face, hands or feet.

Antiplatelet agents

Advise pregnant women at high risk of pre-eclampsia to take 75-150 mg of aspirin daily from 12 weeks until the birth of the baby. Women at high risk are those with any of the following

• Hypertensive disease during a previous pregnancy
• Chronic kidney disease
• Autoimmune disease such as SLE or APLS syndrome
• Type 1 or type 2 diabetes
• Chronic hypertension

Advise pregnant women with more than 1 moderate risk factor for preeclampsia to take 75–150 mg of aspirin daily from 12 weeks until the birth of the baby. Factors indicating moderate risk are:

• first pregnancy
• age 40 years or older
• pregnancy interval of more than 10 years
• body mass index (BMI) of 35 kg/m2 or more at first visit
• family history of pre-eclampsia
• multi-fetal pregnancy. [2010, amended 2019]

References

• NICE guidance