Module 3: Preeclampsia and hypertension in pregnancy

Hypertensive disorders of pregnancy occur in about 10% of women.

There are 3 different types of hypertensive disorders in pregnancy.

• 1. Chronic /essential hypertension, where hypertension has either existed prior to the pregnancy or occurs before 20 weeks gestation.
• 2. Gestational hypertension (GH), where hypertension is of new onset after 20 weeks of gestation with blood pressure ≥140/90 on 2 recordings 4 hours apart. Approximately 25% of these women go on to develop preeclampsia.

• 3. Preeclampsia, a multisystem disorder unique to pregnancy characterised by hypertension and involvement of one or more other organ systems and / or of the fetus including proteinuria, protein creatinine ration (PCR) >30mg/mmol or >0.3g/24hr), creatinine >90μmol/L, oliguria <80mL/4 hr, platelets <100, evidence of haemolysis or DIC, elevated liver transaminases, severe epigastric/RUQ pain, eclampsia (seizures), hyper-reflexia with sustained clonus, persistent new headache or persistent visual disturbance, pulmonary oedema, fetal growth restriction (SGA with abnormal Doppler waveforms).

These conditions are most common in a first pregnancy but women with previous pregnancies complicated by hypertensive conditions or specific medical conditions are at the most risk.

 Risk factors for Preeclampsia

Have a look at this bar chart from a National Women's Health study. You can see that hypertensive conditions of pregnancy are predominantly term diseases with 90% of GH and about 60% of preeclampsia occurring at term (≥37 weeks). However, preeclampsia occurring earlier in pregnancy is usually more severe and more likely to affect the fetus as well as the mother. Preeclampsia is a leading cause of maternal mortality and morbidity and imposes significant risks for the fetus including problems with growth, abruption, stillbirth and the need for early delivery causing prematurity GH and preeclampsia (or even eclampsia) may also present for the first time after delivery in the postnatal period and you should remain aware of this for any women developing signs or symptoms after delivery particularly in the first 48-72 hours.

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