Hypertensive Disorders of Pregnancy - Dr Thomas Carins Australian South Asian Healthcare Association (ASHA) Maternal Health Education Program

Hypertensive Disorders Hypertensive disorders affect 3 – 5% of pregnancies Chronic Hypertension Hypertension arising prior to 20 weeks Gestational Hypertension Hypertension arising after 20 weeks without end-organ dysfunction Preeclampsia on chronic hypertension Systemic features of preeclampsia developing after 20 weeks in a person with chronic hypertension

Hypertensive Disorders Preeclampsia Hypertension arising after 20 weeks accompanied and one of: Renal – low urine output, proteinuria (PCR >30mg/mmol) Haematological – low blood count, low platelet count Hepatic – severe epigastric pain, elevated liver enzymes Neurological – seizures, hyper-reflexia, stroke, visual changes Pulmonary oedema Fetal growth restriction Placental abruption

New Onset Hypertension If hypertension develops after 20 weeks: Usually requires multiple BP measurements over hours Assess for symptoms of preeclampsia Headache, RUQ pain, visual disturbances, nausea and vomiting, reduced fetal movements Investigations that can take place at hospital: Blood tests (kidney/liver function, full blood count) Urine dipstick (2+ protein) US/fetal heart rate monitoring

Chronic Hypertension Hypertension Mild: 140-149/90-99 mmHg Moderate: 150-159/100-109 mmHg Severe: >160/110 mmHg Difficult to diagnose if woman has not presented prior to 20 weeks Treatment reserved for moderate-severe HTN: Methyldopa 250mg-500mg TDS Labetalol 100-400mg TDS Nifedipine 20-60mg (XR) daily

Gestational Hypertension Risks of hypertension Small babies Risk of post-partum haemorrhage Risk of haemorrhagic stroke Poor neonatal outcomes

Preeclampsia One of the leading causes of maternal death 50% of women with gestational hypertension develop preeclampsia No single cause identified. Due to a defect in placental development which then causes systemic changes leading to end organ damage For women with a previous history of preeclampsia or current essential hypertension: low dose aspirin throughout pregnancy should be given (100mg daily) to prevent preeclampsia.

Active Management Delivery of placenta is the only cure Severe headache, visual disturbances, hyper-reflexia All indicate impending seizure! Severe Preeclampsia necessitates transfer to hospital Prevent seizures Lower blood pressure Deliver

Antihypertensives Tight control risks small babies Poor control risks intra-cerebral haemorrhage During acute treatment must have fetal heart rate monitoring Drug Dose Route Protocol Labetolol 25 – 50 mg IV bolus over 2 mins Repeat 15-30 mins PRN Nifedipine 10 – 20 mg Oral Repeat >45 mins PRN Hydralazine 5 – 10 mg IV bolus Repeat after 30 mins

Magnesium Sulphate Most effective method in preventing seizures Indications: Severe preeclampsia Severe headache Visual disturbances Severe RUQ pain Clonus >3 beats HELLP syndrome (haemolysis, elevated liver enzymes, low platelets) Loading: 4-6g in 100ml normal saline over 20 mins Maintenance: 1-3 g/hr

Eclampsia Grand mal seizure from 60-90 seconds 1.6–10 /10 000 live births Requires immediate attention. Most self-resolving but require monitoring of airway and vital signs. May or may not: Precede severe preeclampsia Hypertension Post-partum

Eclampsia Management Does not respond to anti-convulsants (Diazepam) It is not cerebral in nature Treatment DRS ABCD Prevent maternal injury MgSO4: If already infusing, giver further 2g bolus Stabilise and deliver: Does not necessarily require caesarean section

References Majority of advice from Advanced Life Support in Obstetrics (ALSO) Asia Pacific. Obstetrics and Gynaecology: An evidence based guide. Abbott et al 2005.