Introduction

Hypertension affects 5-10% of pregnancies [1] and may be classified into three groups based on both the time of onset and clinical manifestations:

  1. Pre-exisiting or essential hypertension: presents at less than 20 weeks gestation
  2. Pregnancy induced hypertension (PIH): hypertension with no proteinuria
  3. Pre-eclampsia [2]

 

Pre-eclampsia is a syndrome that affects 3% of pregnancies [1]. It can be defined as PIH with proteinuria (>300 mg of protein in 24hrs) and with or without oedema [3] that presents after 20 weeks gestation in women with no previous hypertension.

    Risk Factors



                                                                                                                                              [3]

    Presentation

    Pre-eclampsia has considerable variability in presentation. The condition may be asymptomatic, so regular antenatal screening is important. On the other hand symptomatic pre-eclampsia may present with:

    • Headache
    • Vomiting
    • Tachycardia
    • Visual disturbance - blurred or altered
    • Epigastric pain
    • Hyperreflexia
    • Irritability [3]

    Management

    The severity of pre-eclampsia is based upon blood pressure. It is important to manage each patient individually with management based on disease severity.

    The following breifly explains the management of the different degress of pre-eclampsia.

       

      Mild pre-eclampsia

      BP is between 140/90 and 149/99 mmHg

      • Admit to hospital
      • No treatment
      • Monitor blood pressure - minimum 4 times daily
      • Blood tests: renal function, FBC, bilirubin, transaminases [4]

       

      Moderate pre-eclampsia

      BP is between 150/100 and 159/109 mmHg

      • Admit to hospital
      • Oral labetalol or methyldopa or nifidipine
      • Monitor blood pressure - minimum 4 times daily
      • Blood tests: renal function, FBC, bilirubin, transaminases [4]

       

      Severe pre-eclampsia

      Severe pre-eclampsia is either-

      a)BP>160/110 mmHg with proteinuria (>0.5g/day) or;

      b) BP 140/90 mmHg with proteinuria and one or more symptoms

        • Admit to hospital
        • Oral labetalol or methyldopa or nifidipine
        • Monitor blood pressure - more than 4 times daily
        • Blood tests: renal function, FBC, bilirubin, transaminases [4]

          Detailed Management of Severe Pre-eclampsia

          Maternal

          • Check BP every 15 minutes 
          • Check oxygen saturation levels
          • Prophylaxis: magnesium sulphate 4g IVI in 100ml 0.9% saline, over a 15 minute period
          • Monitor urine output
          • Monitor temperature
          • FBC, U&Es, LFTs, Creatinine
          • Clotting studies if platelets are below 100 x 10^9/L 

           

          Fetal

          • Heart rate
          • Ultrasound scan - fetal growth and liquor volume [3]

          Investigation Findings in Pre-eclampsia

          • FBC - reduced platelets, reduced haemaglobin
          • Renal function - increased urea, increased creatinine, increased urate, urine output reduced
          • Liver function - increased alanine transaminase (ALT), increased aspartate transaminase (AST) [2]

          Treatment for Pre-eclampsia

          The only cure is delivery of the fetus.

          At the time of labour - prescribe H2 blockers

          It is important to monitor the patient after delivery as there is still a risk of developing eclamptic fits post partum [3].

          Prevention

          Reducing the risk of pre-eclampsia:

          • Antiplatelet drugs for high risk women* - 75mg daily from 12 weeks gestation [4]

          *

          Chronic hypertension

          Diabetes

          Hypertension in previous pregnancy

          Autoimmune disorder - systemic lupus erythematosus, antiphospholipid syndrome

          Chronic kidney disease

          Future risk

          How will pre-eclampsia affect future pregnancies?

          The risk of developing the following complications in a future pregnancy in women who have had pre-eclampsia:

          • Gestational hypertension - 13-52%
          • Pre-eclampsia - up to 16% or 25% if they previously suffered from either severe pre-eclampsia, HELLP syndrome or eclampsia and with delivery before 34 weeks [4]

          Eclampsia

          Pre-eclampsia may progress to eclampsia if not properly managed. Pre-eclamptic women are at risk of developing eclampsia; generalised seizures that can result in maternal death from the development of organ failure- renal, liver or heart. It can also cause cerebral haemorrhage and may also result in intrauterine death of the fetus. It is therefore important to prevent the onset of eclampsia in women who are thought to be at risk. The condition occurs more commonly in first pregenancy but can occur in multiparous women [5].

          Prevention measures for the onset of eclampsia:

          Careful management of the patient is important

          • Regular BP checks and antenatal checks
          • Urinalysis
          • Prophylaxis - magnesium sulphate
          • Uterine doppler scans - for high risk patients

          Management of eclampsia

          • First seizure - 4g magnesium sulphate (in 100ml 0.9% saline IVI)
          • Maintainence: 1g magnesium sulphate every hour for 24 hours IVI
          • Recurrent seizures - 2g IVI magnesium sulphate bolus
          • Monitor both respiratory rate and tendon reflexes
          • IV diazepam one dose (5-10mg slowly) if fits continue [3]

          HELLP Syndrome

          HELLP - Haemolysis, elevated liver enzymes and low platelets

          This is a variation of severe pre-eclampsia or may be regarded as a complication of the condition. It occurs in 10-20% of patients with severe pre-eclampsia. 0.5-0.9% of pregenancies develop HELLP syndrome [6].

          Haemolysis is the result of microangiopathic haemolytic anaemia.

          Raised liver enzymes is due to liver involvement, and haemolysis 

          Thrombocytopenia results from increased platelet consumption. Activated platelets attach to vascular endothelial cells that are damaged which causes platelet turnover to increase [6].

          Symptoms

          • Nausea and vomiting
          • Epigastric or right upper quadrant pain
          • Fatigue
          • Visual disturbance
          • Headache

          Investigations

          • LFTs: AST, LDH and ALT increased
          • Blood film: burr cells, polychromasia (evidence of haemolysis) [2]

          Complications



                                                                                                                                                    [6]

          References

          (1) Hutcheon JA, Lisonkova S, Joseph KS. Epidemiology of pre-eclampsia and the other hypertensive disorders of pregnancy. Best Practice & Research in Clinical Obstetrics & Gynaecology 2011 Aug;25(4):391-403.

          (2) Magowan B, Owen P, Drife JO. Clinical obstetrics and gynaecology. 2nd ed. Edinburgh: Saunders; 2009.

          (3) Collier JAB. Oxford handbook of clinical specialties. 8th ed. Oxford: Oxford University Press; 2009.

          (4) NICE. Hypertension in pregnancy. The management of hypertensive disorders during pregnancy, NICE clinical guideline 107. Aug 2010; Available at:www.nice.org.uk/nicemedia/live/13098/50418/50418.pdf.

          (5) Symonds EM, Symonds IM. Essential obstetrics and gynaecology. 4th ed. Edinburgh: Churchill Livingstone; 2004.

          (6) Haram K, Svendsen E, Abildgaard U. The HELLP syndrome: clinical issues and management. A Review. BMC Pregnancy & Childbirth 2009;9:8.

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