The Diagnosis of Preeclampsia in General Practice

Mr. Hayden Waterham

St Vincent's Private Hospital Fitzroy

Preeclampsia is a multi-system disorder unique to human pregnancy. It is characterised by hypertension and involvement of one or more maternal organ systems (including the fetus). 

Accurate determination of blood pressure is of critical importance. The pregnant patient should be seated comfortably with her legs resting on a flat surface and her arm resting at the level of her heart.

Appropriate cuff size is of greater importance as the upper arm circumference has generally increased with the increasing prevalence of obesity in the pregnant population. If the arm circumference is greater than 44cm a thigh cuff should be used. The systolic blood pressure is accepted as the first sound heard (Korotkoff 1) and the diastolic blood pressure is complete disappearance of sounds (Korotkoff 5). 

Hypertension in pregnancy is defined as systolic blood pressure greater than or equal to 140mmHg AND/OR diastolic blood pressure greater than or equal to 90mmHg. Severe hypertension is generally accepted to be present when the systolic is greater than 160mmHg AND/OR diastolic greater than 110mmHg. Serial measurements over a fixed time period can help identify white coat hypertension and therefore avoid unnecessary intervention.

Twenty four ambulatory blood pressure monitoring may also have a role where the patient could not have serial measurements recorded. When hypertension is diagnosed it is critical for the clinical to take further steps in evaluating for preeclampsia. Preeclampsia is hypertension accompanied by one or more of the hollowing signs of organ involvement. 

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Renal involvement 
Significant proteinuria –a spot urine protein/creatinine ratio ≥ 30mg/mmol
Serum or plasma creatinine > 90 μmol/L
Oliguria: <80mL/4 hr 

While renal dysfunction is the most common abnormality it DOES NOT have to be present to make the diagnosis. 

Haematological involvement 
Thrombocytopenia <100,000 /μL 
Haemolysis: schistocytes or red cell fragments on blood film, raised bilirubin, raised lactate dehydrogenase >600mIU/L, decreased haptoglobin 
Disseminated intravascular coagulation  

Liver involvement 
Raised serum transaminases
Severe epigastric and/or right upper quadrant pain. 

Neurological involvement 
Convulsions (eclampsia) 
Hypereflexia with sustained clonus 
Persistent, new headache 
Persistent visual disturbances (photopsia, scotomata, cortical blindness, posterior reversible encephalopathy syndrome, retinal vasospasm) 
Stroke 

Pulmonary oedema 

Fetal growth restriction (FGR)
Estimated fetal weight less than the 10%.

Preeclampsia is a progressive disorder that will inevitably worsen if pregnancy continues. Treatment does not alter placental pathology or change that natural history of the disease. Delivery of the fetus is the definitive management and usually results in the resolution of the disease. 

Consultation with an obstetrician is mandatory upon the diagnosis of the disease in general practice. The immediate management of hypertension and stabilisation of the patient is guided by the severity of the hypertension, the degree of organ involvement and the gestation of the pregnancy. 

Delivery timing, mode and location depends on the severity of the disease, the location of the patient and the facilities available. 

Further reading on the diagnosis and management of hypertensive disorders in pregnancy:

Lowe SA, Bowyer L, Lust K, McMahon LP, Morton M, North RA, Paech M, Said JM SOMANZ Guidelines For The Management of Hypertensive Disorders of Pregnancy 2014. Aust N Z J Obstet Gynaecol. 2015 Oct;55(5):e1-29. 

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