Preeclampsia

Question 1

What is preeclampsia

Answer 1

Disorder of pregnancy characterised by high blood pressure after 20 weeks gestation associated with end organ changes (proteinuria).
Involvement of more than one organ system +/- fetus
HTN is commonly, but not necessarily always, the first feature of preeclampsia

Question 2

Chronic Hypertension

Answer 2

Exists prior to pregnancy or diagnosed <20 weeks

Hypertension unrelated to pregnancy

Question 3

Gestational Hypertension

Answer 3

New onset HTN >20 weeks gestation (BP >140/90 on 2 recordings, 4 hours apart)
No features of preeclampsia
25% develop preeclampsia especially when occurs early (majority of preeclampsia develops >34 weeks)
If BP resolves after 12 weeks = gestational HTN, if HTN persists = chronic HTN

Question 4

What normally happens to BP in pregnancy

Answer 4

Normally in pregnancy, there is systemic vasodilation and a drop in maternal blood pressure, especially diastolic, to account for the added haemodynamic strain as a result of the placenta and developing fetus

Question 5

Severe HTN in pregnancy

Answer 5

THE EARLIER THE GESTATION AT PRESENTATION AND THE MORE SEVERE THE HTN, THE HIGHER LIKELIHOOD OF POOR COUTCOMES

Severe HTN in pregnancy:
Defined as systolic BP of or above 170mmHg +/- a diastolic BP of or above 110mmHg.
All women with severe HTN in pregnancy should be prescribed antihypertensive treatments
This represents the systolic BP above which the risk of maternal mortality and morbidity is increased
It is well understood that pregnancy inherently results in altered cerebral perfusion pressures, if severe hypertension is superimposed on this already physiological change – there is increased risk of cerebral haemorrhage and encephalopathy during pregnancy – hence antihypertensive treatment is essential and should be started immediately but with caution

Question 6

What is the link between preeclampsia and Chronic HTN

Answer 6

Pre-existing HTN – strong risk factor for developing preeclampsia
Woman with chronic HTN develops 1 or more features of preeclampsia after 20 weeks gestation

Question 7

What is the natural progression of preeclampsia.

Answer 7

Natural progression of preeclampsia occurs at an unpredictable rate until delivery and therefore women with preeclampsia should be closely monitored

Question 8

List RF for preeclampsia

Answer 8

Nulliparity 
Extremes of age (<20 or >40 years)
Obesity
Family history - mother or sister with preeclampsia, or first degree relative with HTN 
Previous preeclampsia 
Multiple pregnancy 
Fetal hydrops or molar pregnancy 
Chronic Hypertension 
Chronic Kidney Disease
Diabetes 
Autoimmune condition – SLE, Scleroderma, Antiphospholipid syndrome

Question 9

What medication should be started if any RF are identified.

Answer 9

Aspirin 100mg EC orally, once daily, ideally at bedtime or in the afternoon Commence between 12 – 20 weeks, ideally <16 weeks and the earlier the better. There is no
benefit to starting aspirin after 20 weeks. Stop at 36-37 weeks, as there is a minimal risk of bleeding if women give birth while still taking aspirin

Calcium 1g (elemental) orally, once daily (e.g. Calcium carbonate 1.25g x 2 tablets once daily) 
Commence before 20 weeks gestation and stop at birth

Question 10

Pathophysiology of preeclampia

Answer 10

Although aetiology is poorly understood there are some pathological processes which occur as a result of hypertension in pregnancy and lead to preeclampsia

Evidence suggests that alterations in circulating angiogenic factors such as increases in tyrosine kinase-1 or soluble endoglin and reduced placental growth factor are pathophysiologically important in the development of preeclampsia, and measurement of these factors may have a potential role in future diagnosis. Changes in these factors are measurable both before and after onset of preeclampsia but are not currently included in diagnostic criteria

Question 11

Pre-eclampsia and mum

Answer 11

Other maternal organ dysfunction:
Renal insufficiency (creatinine >90 micromol/L, urine output of <80 mL/4 hour)
Liver involvement - elevated transaminases (aspartate transaminase (AST) and alanine transaminase (ALT)) – at least twice upper limit of normal ± right upper quadrant or epigastric abdominal pain). Note normal ranges are ALT 0-30 units/L and AST 10-50 units/L
Neurological complications (common examples are hyperreflexia when accompanied by clonus, severe headaches and persistent visual scotomata; other examples are eclampsia, altered mental status, blindness, stroke)
Haematological complications (thrombocytopenia – platelet count below 100 × 109/L, haemolysis)
Uteroplacental dysfunction (e.g. fetal growth restriction, abruption).

Question 12

Eclampsia

Answer 12

Rare (8.6/10,000 births)
Headache, visual disturbance or altered LOC are considered symptoms of imminent eclampsia
Preeclampsia leading to new onset of seizures or stroke
Severe manifestation of preeclampsia which can occur before, during or after birth
In rare cases it can be a presenting feature of Preeclampsia