Hypertension in Pregnancy Flashcards
only cure of pre-eclampsia?
delivery of baby
- irrespective of gestational age of baby
what cardiovascular changes occur in pregnancy?
plasma volume increases
CO increases
stroke volume increases
HR increases
slight BP drop in mid-trimester which then rises again slightly
peripheral vascular resistance decreases (to accommodate other changes)
definition of hypertension in pregnancy?
> 140/90 on 2 occasions
or
160/110 once
3 classifications of hypertension in pregnancy?
pre-existing hypertension
pregnancy induced hypertension (PIH)
pre-eclampsia
how is pre-existing hypertension diagnosed?
usually diagnosed before pregnancy
likely to be pre-existing if present in early pregnancy
may be a retrospective diagnosis if BP hasnt resolved within 3 months after delivery
risks of pre-existing hypertension in pregnancy?
PET
IUGR
abruption
when does PIH generally occur?
2nd half of pregnancy
usually resolves within 6 weeks of delivery
high recurrence rate
how is PIH different to pre-eclampsia?
no proteinuria or other features of pre-eclampsia (oedema etc)
better outcomes than pre-eclampsia
although 15% can progress to pre-eclampsia
features of pre-eclampsia?
hypertension
protienuria (>0.3g/l or >0.3g/24hrs)
oedema
diffuse vascular endothelial dysfunction and widespread circulatory disturbance in whichever system affected (cardio, renal etc)
absence does not exclude diagnosis however
may be asymptomatic at time of first presentation
2 sub-types of pre-eclampsia?
early (<34 weeks)
- common
- associated with villous and vascular lesions of placenta
- higher risk of maternal and foetal complications than late
late (>34 weeks)
- more common
- minimal placental lesions
- maternal factors (such as metabolic syndrome etc) can have important roles
- most cases of eclampsia and maternal death in late
phases in pathogenesis of pre-eclampsia?
genetic/environmental predisposition
stage 1
- failure of placental development causing abnormal placental perfusion and ischaemia
stage 2 (matenal syndrome)
- an anti-androgenic state associated with endothelial dysfunction
what changes occur in the placenta in pre-eclampsia?
abnormal placentation and trophoblast invasion leads to failure of normal vascular remodelling
spiral arteries then fail to adapt to become high capacitance, low resistance narrow vessels
placental ischaemia occurs which leads to widepsread endothelial damage and dysfunction
endothelial damage leads to
- increased capillary permeability, CAM expression, prothrombic factors and platelet aggregation and vasoconstriction
what systems can be affected by pre-eclampsia?
CNS renal hepatic haematological pulmonary cardiovascular placental
liver disease in pre-eclampsia?
HELLP syndrome
- haemolysis
- elevated
- liver enzymes
- low
- platelets
features of HELLP syndrome?
epigastric/RUQ pain
abnormal liver enzymes
hepatic capsule rupture
how can pre-eclampsia affect placenta?
fetal growth restriction placental abruption (can cause post partum haemorrhage) intra-uterine death
common symptoms of pre-eclampsia?
headache visual disturbance epigastric/RUQ pain nausea/vomiting rapidly progressive oedema (may vary in timing, progression and order of symptoms)
signs of pre-eclampsia?
hypertension proteinuria oedema abdominal tenderness disorientation small for gestational age intra-uterine fetal death hyper-reflexia/involuntary movements/clonus
how is pre-eclampsia investigated?
urea and electrolytes serum urate (one of the 1st things to increase) LFTs (haemolysis, thrombocytopaenia) FBC coagulation screen urinalysis (protein/creatinine ratio) cardiotocography US (fetal assessment)
how is pre-eclampsia managed?
assess risk if hypertension present <20 weeks - look for 2ndary cause antenatal screening (BP, urine, MUAD) treat hypertension maternal and fetal surveillance timing of delivery
risk factors for pre-eclampsia?
maternal age (>40) maternal BMI (>30) family history parity (higher risk if first) multiple pregnancy previous pre-eclampsia birth interval > 10 years molar pregnancy/triploidy disease is more severe in multiparous women
medical risk factors for pre-eclamspia?
pre-existing renal disease pre-existing hypertension diabetes (pre-existing/gestational) connective tissue disease thrombophilias (congenital/acquired)
what can be used to prevent pre-eclamspia?
low dose aspirin
used in high risk women (renal, diabetes, APS, multiple risk factors, previous pre-eclampsia etc)
150mg commenced before 16 weeks
how does aspirin work?
inhibits COX enzyme which prevents TXA2 synthesis
how can US doppler scan be used in pre-eclampsia?
can be done at 20-24 weeks to visualise the uterine artery and iliac vessels
uterine artery can be measured
- may show notching indicating a high resistance uterine artery implying that placentation hasn’t occurred as expected which hugely increases chance of pre-eclampsia
when are patients referred to the antenatal day care unit (AN DCU)?
BP >140/90
++ proteinuria
increased oedema
symptoms of pre-eclampsia (e.g headache)
investigations will be done but wont stay overnight
when are patients admitted straight away?
BP >170/110 or >140/90 with ++ proteinuria significant symptoms abnormal biochemistry significant proteinuria >300mg/24 hrs need for antihypertensive therapy signs of foetal compromise
what assessment is done as an inpatient?
BP every 4 hrs daily urinalysis input/output fluid balance chart urine PCR if proteinuria on urinalysis bloods (FBC, U&Es, urate, LFTs) basically every day
how is hypertension managed in pregnancy?
treat regardless of cause with MAP >150 there is significant risk of cerebral haemorrhage most people treat is BP >150/100 BP > 17-/110 needs immediate treatment aim for 140-150/90-100
does control of BP reduce risk of developing pre-eclasmpsia?
no
what drugs are used 1st line for hypertension in pregnancy?
methyldopa 250mg bd - 1g tds
labetolol 100mg bd - 600mg qid
nifedipine 10mg bd - 40mg bd
contra-indications in 1st line anti-hypertensives?
methyldopa = depression labetolol = asthma
2nd line drugs in hypertension in pregnancy?
hydralazine 25mg tds - 75mg qid
doxazosin 1mg od - 8mg bd
side effects of 2nd line anti-hypertensives?
doxazosin not safe in breast-feeding
what foetal surveillance is done in pre-eclampsia?
fetal movements daily CTG US - biometry - amniotic fluid index - umbilical artery doppler
when should the baby be delivered in pre-eclampsia?
mother must be stabilised before birth
try and leave it as long as possible if baby is pre-term
give steroids
- betamethasone
- dexamethasone
usually delivered within 2 weeks of diagnosis
indications for delivery of baby?
term gestation inability to control BP rapidl deteriorating biochemistry/haematology eclampsia other srisis foetal compromise (abnormal US or CTG)
crises in pre-eclampsia?
eclampsia HELLP syndrome pulmonary oedema placental abruption cerebral haemorrhage cortical blindness DIC acute renal failure hepatic rupture
what happens in eclampsia?
tonic-clonic seizure occuring with features of pre-eclampsia
>1/3 will ahev seizure before onset of hypertension/proteinuria
ante-partum/antra-partum/post-partum
more common in teenagers
associated with ischaemia/vasospasm
how is severe pre-eclampsia / eclampsia managed?
control BP
- IV labetolol
- IV hydralazine
stop/prevent seizures
- loading dose = 4g IV Magnesium sulphate over 5 mins + maintenance dose of 1g/hr IV, give another 2g is further seizures, consider 10mg IV diazepam in persistent seizures
fluid balance
- no treatment if oliguria,manage pulmonary oedema, run patient “dry” - 80ml/hr
delivery
- aim for vaginal birth, control BP, epidural, continuous foetal monitoring, avoid ergometrine, caution with IV fluids
post-partum management of pre-eclampsia?
breast feeding encouraged contraception BP management counselling/debrief future risk depends on other medical factors and is gestation dependent consider long term cardio risk
