Hypertension in Pregnancy Flashcards
what is the commonest cause of iatrogenic prematurity
pre eclampsia
proteinuria + oedema + hypertension = ?
pre eclampsia
what is the only definitive Tx for PET?
birth
what CVS changes occur in pregnancy
plasma volume increases by 45%
CO increases by 30-50%
stoke volume increased by 25%
HR increases ny 15-25%
to compensate for this peripheral vascular resistance decreases by 15-20%
what changes happen to BP in pregnancy
minimal dip mid pregnancy then increases (not by as much as previously thought)
what is diagnostic of hypertension in pregnancy
> /= 140/90 on 2 occasions or >160/110 once
or >30/15 compared to first trimester NP
what are the three forms of HPTx in pregnancy
Pre-existing hypertension
Pregnancy Induced Hypertension (PIH)
Pre-eclampsia
when might pre existing hypertension be diagnosed
prior to pregnancy
in early pregnancy (PET and PIH tend to occur in later pregnancy)
may be retrospective diagnosis (PET and PIH resolve after birth) if BP abnormal after 3 months of delivery
what are the risk of pre existing HPTx in pregnancy
PET
IUGR
abruption
what secondary causes should you consider in pre existing HPTx
renal/ cardiac
cushings
conns
phaeochromocytoma
what are the features of pregnancy induced hypertension
happens in 2nd half of pregnancy
resolves within 6 weeks of delivery
no proteinuria or other symptoms of PET
what are the risks of PIH
(better outcomes than PET)
15% progress to PET
recurrence high
what are the features of pre eclampsia
hypertension
proteinuria (>0.3g/l)
oedema
is a multisystem disorder so can present in many ways- absent of any of these symptoms does not exclude diagnosis
may be asymptomatic at time of first presentation
what systems does pre eclampsia affect
diffuse vascular endothelial dysfuntion= widespread circulatory disturbance:
- renal (AKI/ failure)
- hepatic
- cardiovascular
- haematology (HELLP)
- CNS (seizures)
- placenta (risk of IUGR, abruption, still birth, IUD)
what are the classifications of pre-eclampsia
early (<34 weeks):
uncommon
associated with extensive villous and vascular lesions of the placenta
higher risk of maternal and fetal complications
late (>/=34 weeks): most common minimal placental lesions maternal factors (esp metabolic syndrome and pre existing hypertension) have important role follows more benign course
in pre eclampsia when do most cases of eclampsia/ maternal deaths occur
in late disease
what is the pathogenesis of pre eclampsia
genetic/ environmental predisposition
1.abnormal placental perfusion causing placental ischaemia:
-abnormal placental and trophoblast invasion
-failure of vascular remodelling (Spiral arteries fail to adapt to become high capacitance, low resistance vessels- usually have smooth muscle layer removed and dilate but in pre eclampsia this doesnt happen and vessels remain narrow and highly resistant)
-Placental ischaemia = widespread endothelial damage and dysfunction by releasing pro inflammatoru proteins that activate endothelium:
increase Capillary Permeability
increased Expression of CAM
increased Prothrombotic Factors
increased Platelet aggregration
Vasoconstriction (causes kidneys to retain more water)
- maternal syndrome- an anti-angiogenic state associated with endothelial dysfunction
- hypertension (due to vasoconstriction and water retention)
- oedema (increased vascular permeability)
- proteinuria (kidney damage)
what is the HELLP syndrome in pre eclampsia
due to endothelial dysfuntion and vasospasm: Heamolysis (due to thrombi in vessels) Elevated Liver enzymes Low Platelets (used up to form thrombi)
develops in 10-20% of women with severe pre eclampsia/ eclampsia
what maintains endothelial health in normal pregnancy
VEGF And TGF- β 1
what is there an imbalance of in PET
angiogenic and antiangiogenic factors
what are the features of liver disease in PET
epigastric/ RUQ pain
abnomal liver enzymes
hepatic capsule rupture
HELLP syndrome
what do signs of liver disease in PET suggests
its severe/ in late stages
what is placental abruption
premature separation of the placenta causing painful antepartum haemorrhage - may be first presentation of PET
what are the SYMPTOMS of PET
headache visual disturbance epigastric/ RUQ pain (liver) nausea/ vomiting rapidly progressing oedema (rings getting stuck on)
presentations will vary in timing, progression and order of symptoms between patients
what are the SIGNS of pre eclampsia
hypertension proteinuria oedema abdominal tenderness oedema abdominal tenderness disorientation small for dates fetus IUD hyper reflexia/ involuntary movements/ clonus
what type of haemorrhage will a low lying placenta cause
painless antepartum haemorrhage
what Ix into PET
U&Es
serum urate (one of first things you see is rise in serum urate)
liver function tests (look for HELLP syndrome)
FBC (haemolysis and thrombocytopenia- low platelets)
coagulation screen
urinalysis for protein creatinine ratio (>30 significant)
cardiotocography
USS for fetal assessment
what is the management plan for hypertension in pregnancy
assess risk at booking
if HTPx <20 weeks look for secondary cause
antenatal screening- BP, urine, maternal uterine artery doppler
treat hypertension
maternal and fetal surveillance
plan for/ time delivery
what are the risk factors for PET
maternal age (<20/ >35) maternal BMI (higher) FMHx parity (higher if first pregnancy) multiple pregnancy previous PE birth interval >10 years molar pregnancy/ triploidy pre existing medical Hx inc HPTx, diabetes, APS, thrombophilia, autoimmune disease
mutliparous women develop more severe disease
what is early severe hypertension in pregnancy strongly associated with
molar pregnancy
what are the medical risk factors for PET
Pre-existing renal disease Pre-existing hypertension Diabetes (pre-existing/gestational) Connective tissue disease Thrombophilias (congenital / acquired. = anything that makes you more like to clot, acquired more common (e.g. APS) associated with placenta thrombosis)
what can be given to prevent PET
low dose aspirin 150mg
commence before 16 weeks
who should take low dose aspirin to prevent PET
high risk women: -renal, DM, APS, multiple risk factors, previous PET -two moderate risk factors or -one high risk factor
what investigation can predict PET
maternal uterine artery doppler
-measures resistance in spiral vessels (should go from high resistance and low capacity before preg to low resistance high capacity during preg)
what are the possible findings on a MUAD
normal= low resistance wave form
high resistance wave form= low flow in diastole due to high resistance in placenta = increase surveillance
when should you refer a women to an antenatal day care unit
if BP >/= 140/90
++ proteinuria
++ oedema
symptoms (especially persistent headache)
when should you admit a pregnant women with worries of PET
BP >170/110 OR >140/90 with (++) proteinuria
Significant symptoms - headache / visual disturbance / abdominal pain
Abnormal biochemistry
Significant proteinuria - >300mg / 24h
Need for antihypertensive therapy
Signs of fetal compromise
what inpatient assessment is done for inpatient PETs
4 hourly BP daily urinalysis input/ output fluid balance chart urine PCR if proteinuria on urinalysis bloods- FBC, U&Es, urate, LFTs, minimum 2x per week
what are the rules for treating HTPx in pregnancy
treat regardless of cause
usually treat if >150/100
BP>/= 170/100 requires immediate emergency Tx
dont lower BP too much as HPTx is whats keeping blood flow through placenta - might cause underperfusion and fetal distress
does treating BP reduce risk of PET
no as underlying process still ongiong
what BP should you aim for in pregnancy
140-150/90-100 mmHg
with MAP >/=150 mmHg what is there significant risk of
cerebral haemorrhage
what is the treatment for hypertension in pregnancy
methyldopa (alpha agonist) 250mg bd- 1g tds labetolol (alpha and beta antagonist 100mg bd- 600mg qid nifedipine SR (Ca channel antagonist) 10mg bd- 40mg bd
2nd line:
hydralazine (vasodilator) 25 mg tds - 75 qid
doxazocin (alpha antagonist) 1mg od- 8mg bd
what hypertensives should you avoid in pregnancy
diuretics and ACEi
what is methyldopa CI in
depression
what is labetolol CI in
asthma (is an alpha and beta blocker)
are the antihypertensive drugs okay to breastfeed with
yes- except from doxazocin
how can you survey the fetus in a hypertensive mother
monitor fetal movements (can feel from 20 weeks, should have felt by 24 weeks)
CTG daily
USS- biometry (abdo circumference), amniotic fluid index (marker of fetal renal function), umbilical artery doppler (assess resistance within fetal circulation)
what are the possible results of a fetal umbilical artery doppler
normal
absent end diastolic flow
reversed end diastolic flow= high resistance, most severe, pre terminal sign, have 4 days to deliver
what rules for delivery in PET
Mother must be stablised before birth
Consider expectant management if pre-term
Steroids- prevent resp morbidity (2 doses 24hrs apart)
Most women delivered within 2 weeks of diagnosis
Mode of birth dependent on gestation, parity, maternal/fetal condition, maternal preference
aim for vaginal
epidural anaesthesia - lowers maternal BP
continuous fetal monitoring
avoid ergometrine (given to prevent haemorrhage but is a hypertensive)
caution with IV fluids (pulmonary oedema)
what are indications for birth in PET
term gestation inability to control BP rapidly deteriorating biochemistry/ haematology eclampsia (had an eclamptic seizure) other crisis fetal compromise (abnormal USS/CTG)
what possible crises can occur in PET
eclampsia HELLP syndrome pulmonary oedema placental abruption cerebral haemorrhage cortical blindness disseminated intravascular coagulopathy acute renal failure hepatic rupture
what is eclampsia
tonic clonic seizure occuring with features of pre eclampsia
when do eclamptic seizures occur
> 1.3 will occur before onset of hypertension/ proteinuria
antepartum 38%
intrapartum 16%
post partum 44%
who is more likely to get eclampsia
teenagers
what is the management of severe PET/ eclampsia
control BP (IV labetolol or IV hydralazine)
stop/ prevent seizures
fluid balance
delivery
what is the seizure treatment/ prophylaxis in eclampsia
magnesium sulphate
loading dose: 4g IV over 5 minutes
maintenance dose: IV infusion 1g/hr
if further seizures 2g
if persistent seizures consider diazepam 10mg IV
what is the main cause of maternal death in PET
pulmonary oedema
what cause pulmonary oedema in pregnancy
capillary leak, fluid overload, cardiac failure
what test if you are worried about renal function in PET
urine osmolality
what fluid balance volume for PET
80 ml/h
safer to give less as risk of pulmonary oedema
