Hypertension in Pregnancy Flashcards
How common is hypertension in pregnancy?
Affects 10-15% of all pregnancies = 14% of maternal deaths due to hypertension
What is the most common cause of iatrogenic prematurity?
Pre-eclampsia
What are some CVS changes that occur during pregnancy?
Plasma volume increases by 45% Cardiac output increases by 30-50% Stroke volume increases by 25% Heart rate increases by 15-25% Peripheral vascular resistance decreases by 15-20%
What is needed to make a diagnosis of hypertension?
BP >= 140/90 mmHg on two occasions
What are some reasons for hypertension during pregnancy?
Pre-existing hypertension, pregnancy induced hypertension or pre-eclampsia
When is pre-existing hypertension likely?
If hypertension occurs in early pregnancy
May be retrospective diagnosis if BP hasn’t returned to normal after 3 months post-delivery
What are the risks associated with pre-existing hypertension?
Pre-eclampsia (x2), IUGR, abruption
When does pregnancy-induced hypertension usually present?
In second half of pregnancy = resolves within 6 weeks of delivery
What are the features of pregnancy-induced hypertension?
No proteinuria or other features of pre-eclampsia
15% progress to pre-eclampsia
High rate of recurrence
What are the symptoms of pre-eclampsia?
Hypertension, proteinuria (>=0.3 g/L), oedema
May be asymptomatic at time of first presentation
What occurs in pre-eclampsia?
Diffuse vascular endothelial dysfunction with widespread circulatory disturbance due to placental ischaemia
What are the two types of pre-eclampsia?
Early = <34 weeks gestation Late = >=34 weeks gestation
What are some features of early pre-eclampsia?
Uncommon = 12% of all pre-eclampsia
Associated with extensive villous and placental lesions
Higher rat of complications than late type
What are some features of late pre-eclampsia?
Majority of pre-eclampsia = 88% Minimal placental lesions Maternal factors (e.g hypertension) have important role
How does having a first degree relative affected by pre-eclampsia increase risk?
3x higher risk if mother or sister has pre-eclampsia
20-25% higher if mother, up to 40% if sister
How do genetic and environmental factors lead to pre-eclampsia?
Create conditions leading to defective deep placentation
What are the stages of pre-eclampsia?
1 = abnormal placental perfusion causing placental ischaemia 2 = maternal syndrome, anti-angiogenic state associated with endothelial dysfunction
What causes failure of normal vascular remodelling in pre-eclampsia?
Abnormal placentation and trophoblast invasion = spiral arteries fail to adapt to become high capitance-low resistance vessels
What does endothelial activation cause in pre-eclampsia?
Increased capillary permeability, expression of CAM, prothrombotic factors and platelet aggregation
What do VEGF and TGF-beta1 do in a normal pregnancy?
They maintain endothelial health
What do sFlt1 and sEng do?
Antagonise VEGF and TGF-beta1 = secreted in excess in PE, cause imbalance between angiogenic and anti-antiangiogenic factors
What systems are affected by pre-eclampsia?
CNS, renal, hepatic, pulmonary, placental, CV and haematological
How can pre-eclampsia affect the hepatic system?
Epigastic/RUG pain, abnormal liver enzymes, hepatic capsule rupture, HELLP syndrome
What are the features of HELLP syndrome?
Haemolysis, elevated liver enzymes, low platelets
What are some feature of placental disease cause by pre-eclampsia?
Foetal growth restriction, placental abruption, intrauterine death
What are the symptoms of pre-eclampsia?
Headache, visual disturbance, epigastic/RUQ pain, nausea and vomiting, rapidly progressive oedema
What are the signs of pre-eclampsia?
Hypertension, proteinuria, oedema, abdominal tenderness, disorientation, small for gestational age foetus, intrauterine foetal death, hyper-reflexia
What investigations are done for pre-eclampsia?
Us & Es, serum urate, LFTs, FBC, coagulation screen, urine protein:creatine ratio, cardiotocography, US for foetal assessment
What is the basic management for pre-eclampsia?
Treat hypertension
Maternal and foetal surveillance
What are the risk factors for pre-eclampsia?
Maternal age >45 or BMI >30
Family history, first pregnancy or multiple pregnancy
Previous PE or birth interval >10 years
Molar pregnancy/triploidy
Pre-existing renal disease or hypertension
Diabetes = pre-existing or gestational
Connective tissue disease or thrombophilias
What is the mechanism of aspirin?
Inhibits COX which prevents TXA2 synthesis
Which women is pre-eclampsia more severe in?
Multiparous women
How is aspirin used to treat pre-eclampsia?
150mg dose commenced before 16 weeks gestation
15% reduction in pre-eclampsia
May be more beneficial in preventing severe early onset pre-eclampsia
What women at considered at moderate risk from pre-eclampsia?
First pregnancy, age >=40, pregnancy interval >10 years, BMI >=35, family history, multiple pregnancy
What women are considered at high risk from pre-eclampsia?
Hypertensive disease during previous pregnancy, CKD, diabetes, autoimmune disease, chronic hypertension
What is done at antenatal screening to detect pre-eclampsia?
BP and urine analysis
MUAD = maternal uterine artery doppler = done at 20-24 weeks
When would you refer a patient to AN DCU?
BP >= 140/90 mmHg, (++) proteinuria, oedema, symptoms (especially persistent headache)
When would you admit a patient?
BP >170/110 OR >140/90 with (++) proteinuria
Significant symptoms = headache, visual disturbance
Significant proteinuria >300 mg/24h
Abnormal biochemistry or signs of foetal compromise
Need for antihypertensive therapy
What is the inpatient assessment for someone with pre-eclampsia?
BP every 4hrs and daily urinalysis
Input/output fluid balance chart
Urine PCR if proteinuria present
Bloods at least 2x week = FBC, Us & Es, LFTs
What does a MAP >= 150 mmHg carry significant risk of?
Cerebral haemorrhage
When would you treat a patient with high BP?
If >=150/100 mmHg = aim for 140-150/90-100 mmHg
Control of BP doesn’t lower risk of pre-eclampsia
What are the first line agents for treating hypertension in pregnancy?
Methyldopa, labetolol, nifedipine SR
What are the features of methyldopa?
Alpha agonist = 250mg twice daily starting dose, contraindicated in depression
What are the features of labetolol?
Alpha and beta antagonist = 100mg twice daily starting dose, contraindicated in asthma
What is nifedipine SR?
Calcium channel blocker = 100mg twice daily starting dose
What are the second line treatments for hypertension in pregnancy?
Hydralazine and doxazocin = avoid use with diuretics and ACE inhibitors
What is hydralazine?
Vasodilator = 25mg three times daily starting dose
What are the features of doxazocin?
Alpha antagonist = 1mg once daily starting dose, not suitable if breastfeeding
What are some methods of foetal surveillance?
Foetal movements and daily CTG
US = biometry, amniotic fluid index, umbilical artery doppler
What is the only cure for pre-eclampsia?
Birth of baby = mother must be stabilised before birth, may use steroids
How soon does birth of the baby follow after pre-eclampsia diagnosis?
Most women deliver within two weeks of diagnosis
What are the indications for delivering the baby?
Term gestation, inability to control BP, rapidly deteriorating biochemistry/haematology, eclampsia or other crisis, foetal compromise (abnormal US/CTG)
What are some crises that occur in pre-eclampsia?
Eclampsia, HELLP syndrome, pulmonary oedema, placental abruption, cerebral haemorrhage, cortical blindness, DIC, acute renal failure, hepatic rupture
What is eclampsia?
Tonic-clonic (grand mal) seizures occurring with features of pre-eclampsia
What is usually the first symptom of eclampsia?
> 1/3 will have seizures before onset of hypertension or proteinuria
When does eclampsia occur?
38% antepartum, 16% intrapartum, 44% postpartum
More common in teenagers
What is eclampsia associated with?
Ischaemia or vasospasm
What is the management of eclampsia?
Control BP and stop seizures, fluid balance, delivery of baby
What antihypertensives can be used to treat eclampsia?
IV labetolol or hydralazine
How are the seizures of eclampsia treated?
Magnesium sulphate = loading dose is 4g IV over 5mins upped to maintenance dose of 1g/hr IV infusion
What should be given if seizures persist after magnesium sulphate is given?
Administer further 2g magnesium sulphate
Consider 10mg IV diazepam if persistent
How common is oliguria in eclampsia?
Occurs in 30% = doesn’t require intervention
How is labour managed in women with hypertension?
Aim for vaginal birth if possible
Control BP and give epidural anaesthetic
Continuous electronic foetal monitoring
What should be avoided during labour in pregnant women?
Ergometrine and use caution with IV fluids
What are the postpartum considerations in women who had hypertension during pregnancy?
Breast feeding and contraception
BP management
Consider longterm CV risk