Hypertensive Disorders in Pregnancy

Introduction

Hypertensive disorders during pregnancy affect approximately 8-10% of all pregnant women and the complications can be associated with significant morbidity and mortality to the mother and baby.



Major Hypertensive Disorders

Major hypertensive disorders that can occur in pregnant women are:

  • Chronic hypertension
    • Hypertension (BP >140/90) that exist before pregnancy or diagnosed in the first 20 weeks of gestation.
  • Gestational hypertension
  • Preeclampsia
    • Hypertension occur after 20 weeks gestation with features of multi-organ involvement
      • Symptoms of pre-eclampsia include severe headache, problems with vision, severe pain below ribs, vomiting and sudden swelling of hands, feet or face accompanied with significant proteinuria and blood pressure greater than 140/90 mg Hg.
    • In 2013, the American College of Obstetricians and Gynaecologists removed proteinuria as an essential criterion for diagnosis of preeclampsia.
  • Eclampsia
    • New-onset generalized seizures in woman with preeclampsia.
  • HELLP syndrome
    • Haemolysis, elevated liver enzymes, low platelets - probably represents a subtype of preeclampsia with severe features.
  • Preeclampsia superimposed on chronic hypertension

An accurate diagnosis, when possible, can be helpful for making management decisions (e.g. timing of delivery, need for antiseizure prophylaxis) and assessing maternal prognosis (e.g. risk for progression in the current pregnancy, recurrence risk in future pregnancies, long-term maternal health risks).



Medication Advice

Pregnant women with chronic hypertension who are already receiving antihypertensive treatment should have their drug therapy reviewed.

  • Stop ACE inhibitors, ARBs, thiazide or thiazide-like diuretics due to an increased risk of congenital abnormalities.
  • Consider labetalol, nifedipine or methyldopa.

Pregnant women who are high risk of developing pre-eclampsia are advised to take aspirin 75-150 mg at night (unlicensed indication) from week 12-16 of pregnancy until the baby is born.

If low dietary calcium intake (<600 mg/day), calcium supplementation 1.2-2.5 g/day orally recommended in women at increased risk of preeclampsia.

Give intravenous magnesium sulphate to women in critical care setting with severe hypertension or severe preeclampsia to reduce the risk of eclampsia, unless patient has myasthenia gravis.

Give corticosteroids to women receiving expectant management at ≤34 weeks gestation to benefit foetal lung maturity.



Following Birth

Following birth, women remaining on antihypertensives should have their treatment reviewed 2 weeks after the birth.

  • Hypertension usually resolves spontaneously within a few weeks (average 16±9.5 days) and is almost always gone by 12 weeks postpartum. However, some cases may take as long as 6 months to resolve.

Women who have been managed with methyldopa during pregnancy should discontinue treatment within 2 days of birth (due to association with maternal depression) and switch to an alternative antihypertensive.

Drug options during breastfeeding include

  • Beta blockers - Propranolol, metoprolol, labetalol
  • Calcium channel blockers - Diltiazem, nifedipine, nicardipine, verapamil
  • Diuretics - Hydrochlorothiazide <50 mg/day (Theoretically, diuretics may reduce milk volume.)
  • ACE inhibitors - Captopril and enalapril (Newborns may be more susceptible to hypotension.)

There is no information use of angiotensin II receptor blockers (ARBs) during breastfeeding.



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