Pregnancy-Induced Hypertension

Question 1

A 31-year-old primiparous female is found to have a blood pressure of 183/96mmHg at a routine midwife appointment. She is 37 weeks pregnant and has no other medical conditions.

What is the definition of pregnancy-induced hypertension?

Answer 1

• Pregnancy-induced hypertension is hypertension (more than 140/90mmHg) that develops after 20weeks of gestation (more than 140/90 mmHg) but with no proteinuria.

Question 2

How should this patient be managed?

Answer 2

• Full history and examination focusing on cardiovascular history and risk factors:
• Check whether the patient had pre-existing hypertension.
• Any symptoms of hypertension: headache, changes in vision, dizziness.
• Senior midwife assessment including CTG.
• Urgent medical treatment of severe hypertension according to the NICE guidelines:
• Admit to hospital.
• Measure blood pressure every 15 minutes until controlled below
  160/110 mmHg.
• Blood tests: full blood count, liver function tests, renal function (U+E) and PCR.
• First-line treatment: labetalol PO (200mg) or IV (50mg bolus followed by infusion).
• Nifedipine or methyldopa can be used if labetalol is ineffective or contraindicated. Do not give sublingual nifedipine as excessively rapid hypotension may occur and foetal condition may be compromised.
• Aim for a blood pressure of <135/85 mmHg.

Question 3

The patient’s blood pressure is controlled and she is discharged home on oral labetalol. Four days later she presents with a severe headache and visual changes.

What is the definition of pre-eclampsia?

Answer 3

• Pre-eclampsia is hypertension (>140/90mmHg) that develops after 20 weeks of gestation with proteinuria, which is defined as one of:
• 2+ of proteinuria on a standard urine dipstick on two separate occasions.
• Urine protein: creatinine ratio (PCR) >30 mg/mmol.
• Protein >300 mg in a 24 hour urine collection (rarely done).

Question 4

What are the risk factors for the development of pre-eclampsia?

Answer 4

• Personal or family history of pre-eclampsia.
• Twin pregnancy.
• Increased maternal age (>40 years).
• Pre-pregnancy raised BMI (>35).
• Maternal comorbidities: diabetes, hypertension, renal disease.

Question 5

What are the goals in the management of this patient?

Answer 5

• Blood pressure control and strict fluid balance prior to delivery.
• Fetal monitoring (CTG).
• Prevention of progression to eclampsia.
• Close monitoring of the patient with senior obstetric, anaesthetic and midwifery input and early escalation when appropriate.

Question 6

What is the indication for treatment with magnesium sulphate?

Answer 6

• Treatment of eclamptic seizures (4g IV over 10 minutes followed by an infusion of 1 g/hour for 24 hours).
• Patients with severe symptomatic pre-eclampsia.

Question 7

The patient is induced and would like an epidural. How do you proceed?

Answer 7

• The decision to site an epidural requires a risk-benefit assessment for the patient. Most individuals will benefit from neuraxial blockade, not only because of the peripheral vasodilation that occurs but also because the analgesia achieved will obtund the hypertension that occurs with contractions.
• Assessment of the patient should include any relative or absolute contra-indications to epidural placement.
• In this case, if the decision to site an epidural is made, the coagulation status of the patient should be verified first. Care must be taken to avoid large fluid boluses and to closely monitor the blood pressure following careful loading of the epidural. Early and judicious use of vasopressor agents should be used in the event of hypotension.

Question 8

What are the risks associated with an epidural?

Answer 8

Common:

• Hypotension.
• Increased incidence of instrumental delivery (not if the concentration of bupivacaine is maintained at 0.1% or below).
• Increased use of uterotonics (oxytocin).
• Increased incidence of maternal pyrexia and therefore antibiotic
  administration, but no increase in maternal or foetal infection risk.
• Increased duration of second stage of labour (marginal).
• Local bruising and short-term backache (but not long-term backache).

Rare:
* Subdural blockade.
* Dural puncture.
* High or total spinal blockade.
* Local anaesthetic toxicity.
* Nerve damage.
* Epidural abscess.
* Epidural haematoma.