Type of hypertensive disorder during pregnancy code N
Identifying and definitional attributes
|Metadata item type:||Value Domain|
|Registration status:||Health, Superseded 05/10/2016|
A code set representing the type of hypertensive disorder during pregnancy.
|Maximum character length:||1|
Collection and usage attributes
|Guide for use:|
More than one code can be selected when reporting on this item. For example, for a woman who has preeclampsia superimposed on chronic hypertension, select both code 2 and code 4. For a woman who develops gestational hypertension which progresses to eclampsia, select codes 1 and 3.
CODE 1 Eclampsia
Eclampsia is characterised by grand mal seizures, hypertension, proteinuria, oedema and may progress to coma. Before a seizure, a patient may experience a body temperature of over 40°C, anxiety, epigastric pain, severe headache and blurred vision. Complications of eclampsia may include cerebral haemorrhage, pulmonary oedema, renal failure, abruptio placentae and temporary blindness (National Centre for Classification in Health, 2010).
CODE 2 Preeclampsia
Preeclampsia is a multi-system disorder unique to human pregnancy characterised by hypertension and involvement of one or more other organ systems and/or the fetus. Proteinuria is the most commonly recognised additional feature after hypertension but should not be considered mandatory to make the clinical diagnosis.
A diagnosis of preeclampsia can be made when hypertension arises after 20 weeks gestation and is accompanied by one or more of the following: Renal involvement, Haematological involvement, Liver involvement, Neurological involvement, Pulmonary oedema, Fetal growth restriction, Placental abruption.
Women with HELLP syndrome (which stands for Haemolysis, Elevated Liver Enzymes, Low Platelet count and is a variant of preeclampsia) are to be included under this code for preeclampsia.
CODE 3 Gestational hypertension
Gestational hypertension is characterised by the new onset of hypertension after 20 weeks gestation without any maternal or fetal features of preeclampsia, followed by return of blood pressure to normal within 3 months post-partum.
CODE 4 Chronic hypertension
This may include essential or secondary hypertension. Essential hypertension is defined by a blood pressure > 140 mmHg systolic and/or > 90mm diastolic confirmed before pregnancy or before 20 completed weeks gestation without a known cause. It may also be diagnosed in women presenting early in pregnancy taking antihypertensive medications where no secondary cause for hypertension has been determined.
Important secondary causes of chronic hypertension in pregnancy include:
• Chronic kidney disease, e.g. glomerulonephritis, reflux nephropathy, and adult polycystic kidney disease.
• Renal artery stenosis
• Systemic disease with renal involvement, e.g. diabetes mellitus, systemic lupus erythematosus.
• Endocrine disorders, e.g. phaeochromocytoma, Cushing syndrome and primary hyperaldosteronism.
• Coarctation of the aorta.
In the absence of any of the above conditions it is likely that a woman with high blood pressure in the first half of pregnancy has essential hypertension.
Diagnosis for eclampsia is to be based on the ICD-10-AM/ACHI/ACS (National Centre for Classification in Health, 2010).
For all other value domains, diagnosis is to be based on Society of Obstetric Medicine of Australia and New Zealand (SOMANZ) Guidelines for the Management of Hypertensive Disorders of Pregnancy. If the clinician does not have information as to whether the above guidelines have been used, available information about diagnosis of hypertensive disorder is still to be reported.
The diagnosis is preferably derived from and substantiated by clinical documentation, which should be reviewed at the time of delivery. However this information may not be available in which case the patient may self-report to the clinician that they have been diagnosed with a hypertensive disorder.
Source and reference attributes
Lowe SA, Brown MA, Dekker G, Gatt S, McLintock C, McMahon L et al. 2008. Guidelines for the management of hypertension in pregnancy. Society of Obstetric Medicine of Australia and New Zealand
The 10-AM Commandments (Coding Matters) in NCCH (National Centre for Classification in Health) 2010. The International Statistical Classification of Diseases and Related Health Problems, 10th Revision, Australian Modification (ICD-10-AM), Australian Classification of Health Interventions (ACHI) and Australian Coding Standards (ACS), Seventh edition. Sydney: University of Sydney.
|Related metadata references:|
Has been superseded by Type of hypertensive disorder during pregnancy code N Health, Superseded 02/08/2017
|Data elements implementing this value domain:|
Female—type of hypertensive disorder during pregnancy, code N Health, Superseded 05/10/2016