Hypertensive Disorders in Pregnancy Flashcards
(24 cards)
What are the normal blood pressure changes in pregnancy?
- Decrease by around 30/15mmHg in the 2nd trimester
- Blood pressure then rises to pre-pregnancy levels by term
Define pregnancy induced hypertension, and the type of disorder this encompasses
When BP >140/90mmHg after 20 weeks
Can be due to:
- Pre-eclampsia
- Gestational hypertension (new HTN after 20 weeks, without proteinuria)
Define pre-existing or chronic hypertension during pregnancy
When BP >140/90 before pregnancy, or before 20 weeks
- Can be primary or secondary (e.g to renal disease, Cushing’s etc.)
- May be existing proteinuria because of renal disease
- Pts with underlying HTN at increased risk of pre-eclampsia
Define pre-eclampsia
Multisystem syndrome, which manifests as new hypertension after 20 weeks, WITH significant proteinuria (>0.3g/24hr)
Outline the aetiology of pre-eclampsia
- Impaired trophoblastic invasion into spinal arteries during placentation → oxidative stress
- Resistance in uteroplacental circulation increases → leads to hypoperfusion and ischemia
- Causes release of inflammatory mediators (sFlt-1, PIGF) → stimulating widespread endothelial damage, end organ
dysfunction, oedema
Describe the different classifications of pre-eclampsia
Classified based on degree of hypertension & presence of symptoms/biochemical/haematological impairment, and based on timing of manifestations
Degree of HTN (increases by 10s):
- Mild: 140/90 to 149/99mmHg
- Moderate: 150/100 to 159/09mmHg
- Severe: 160/110+ mmHg
Degrees of pre-eclampsia:
- Mild or moderate: no severe HTN, no symptoms, no biochemical nor haematological impairment
- Severe: severe HTN and/or with symptoms, and/or biochemical and/or haematological impairment
Timing of manifestations:
- Early: <34 weeks
- Late: >34 weeks
Give some risk factors for the development of pre-eclampsia
High risk if (aspirin given if ANY of):
- Previous hypertensive disease during pregnancy
- CKD
- Autoimmune disease (SLE, antiphospholipid syndrome)
- T1DM, T2DM
- Chronic HTN
Moderate risk (aspirin if >1 of):
- Nulliparous
- Age >40yrs
- Pregnancy interval >10 years
- BMI >35 at booking
- FH of pre-eclampsia
- Multiple pregnancy
Describe the different ways urinary protein can be assessed, and the values in each method that classify proteinuria
Dipsticks (bedside):
- Trace: NS
- 1+: possibly significant proteinuria, quantify
- ≥2+: significant proteinuria likely, quantify
PCR (protein:creatine ratio)
- >30mg/nmol: confirmed significant proteinuria
24hr collection
- >0.3g/24h: confirmed significant proteinuria
Describe the clinical presentation of pre-eclampsia
History
- Can be asymptomatic
- Headache, visual disturbances
- Drowsiness, nausea & vomiting
- Epigastric pain
Examination
- Elevated BP
- Proteinuria
- Oedema (more than expected, not postural)
- Epigastric tenderness
Outline some maternal complications, and the treatment for each of pre-eclampsia
Early onset disease is often more severe. Occurrence of complications is an indication for delivery, regardless of gestation:
- Eclampsia: grand mal seizures –> hypoxia and mortality
Treated with magnesium sulphate - Cerebrovascular haemorrhage
Treatment of HTN should prevent this - Liver and coagulation problems: HELLP syndrome (Haemolysis - dark urine, raised LDH, EL: elevated liver enzymes, LP: low platelets)
Treatment: supportive and magnesium sulphate prophylaxis for eclampsia - Renal failure
Treatment may require haemodialysis - Pulmonary oedema
Treatment with oxygen, furosemide, assisted ventilation may be required
Outline foetal complications of pre-eclampsia
- Mortality and morbidity
- Growth restriction (early onset pre-eclampsia)
- Preterm delivery
- Increased risk of placental abruption
Describe the investigations for diagnosis of pre-eclampsia and for identifying complications
Confirming diagnosis:
- BP
- Proteinuria (>0.3g/24hr, or >30mg/nmol on PCR)
Monitoring maternal complications
- Bloods: uric acid, Hb, platelets, LDH, LFTs (ALT will rise in HELLPP), renal function (rapidly rising creatinine)
- Eclampsia: CT head post-seizure
Monitoring foetal complications
- US scan to estimate foetal weight
- Umbilical artery Doppler, CTG (monitoring foetal well-being)
Outline some screening tools for picking up pre-eclampsia
- Early: Uterine artery Doppler at 20/40
- Late: ratio of sFlt-1:PIGF
What is used for prevention of pre-eclampsia?
- Low dose aspirin (75mg) daily, starting before 16/40
Simply outline the main domains of management for pre-eclampsia
- Assessment: does pt require admission
- Drugs
- Timing of delivery
- Conduct of delivery
- Postnatal care
Describe the criteria for admission in patients with pre-eclampsia and explain how pts not admitted are followed up
Criteria for admission
- Symptoms
- Proteinuria (>30 PCR, or >0.3g/24h)
- Severe HTN
- Growth restriction, abnormal umbilicate artery Doppler or abnormal CTG
- Abnormal sFlt-1/PIGF assay
Patient’s not admitted are managed in outpatients
- BP and urinalysis repeated x2 a week
- US every 2-4 weeks
Describe the medical management for pre-eclampsia
Antihypertensives (if BP reaches 150/100)
- Oral nifedipine, IV labetalol maintenance
Prevention of eclampsia
- IV Magnesium sulphate
Toxicity can cause respiratory depression and hypotension, which is preceded by loss of patellar reflexes (test regularly)
If magnesium is required, delivery is indicated
- Steroids to promote foetal lung maturity if <34/40
Outline the timing of delivery in mothers with pre-eclampsia
Pre-eclampsia is cured only by delivery
- Should be delivered by 36 weeks
- <36 weeks: conservative management (steroids, intensive maternal and foetal surveillance, CTB, fluid balance)
When does delivery usually take place for gestational hypertension?
- Monitoring for deterioration
- Delivery by 40/40 is usual
Describe the management of conduct of delivery in pre-eclampsia
- <34/40: severe growth restriction –> C-section
> 34/40: induction with prostaglandins usually
- Epidural
- Foetal monitoring with CTG
- Antihypertensives used in labour
- If >160/110mmHg: avoid pushing in 2nd stage
- Oxytocin rather than ergometrine for 3rd stage
Describe the main management post-natally of mothers with pre-eclampsia
Often takes 24hrs for severe disease to improve, it can also worsen during this time
Bloods
- LFTs, platelets, renal function
Fluid balance
- IV fluid restricted to 80mL/h (due to risk of pulmonary oedema)
- Urine output monitoring: if CVP high, give furosemide, if CVP low, fluid is given
Blood pressure
- Maintained at 140/90
- Beta blocker
2nd line: nifedipine, ACEi
Long term management
- Follow up with GP and midwives
- If proteinuria and HTN persistent at 6 weeks: referral to renal or HTN clinic
Describe the clinical features and complications of pre-existing hypertension in pregnancy
Clinical features
- Symptoms usually absent
- Proteinuria at booking
- Secondary causes: renal bruits (RAS), radio-femoral delay (coarctation of aorta)
Complications
- Pre-eclampsia
- IUGR
- Prematurity
- Placental abruption
Outline investigations for pre-existing hypertension in pregnancy
To identify secondary hypertension
- Two 24hr urine collections for VMA: to exclude pheochromocytoma
- Renal function, US
- Proteinuria, to identify any pre-eclampsia
(Proteinuria may be pre-existing due to pre-existing renal disease)
Describe the management for pre-existing hypertension in pregnancy
Antihypertensives
- Should be changed before pregnancy: ACEi are teratogenic
- Labetalol
- 2nd line: nifedipine
Risk of pre-eclampsia
- High risk, so aspirin 75mg daily is required
- Screening: uterine artery doppler, additional antenatal visits and scans to assess foetal growth
Delivery
- Usually 38-40 weeks
