Hypertensive Disorders in Pregnancy Flashcards
what are the normal blood pressure changes in pregnancy
Blood pressure usually falls by 30mmHg in systolic and 15mmHg in diastolic in the 2nd trimester due to reduced vascular resistance
Hypertension may be a sign of pre-eclampsia due to increased systemic vascular resistance
What is a normal amount of protein excretion in pregnancy
Protein excretion is normal in pregnancy, but in the absence of renal disease it is <0.3g/24hr
what is the diagnostic criteria for pregnancy induced hypertension
> 140/90 after 20 weeks (before that it is considered preexisting)
how do you differentiate between pregnancy induced hypertension and preeclampsia
pre-eclampsia generally has proteinuria whereas in the absence of renal disease pregnancy induced hypertension doesn’t - however this isn’t true 100% of the time
what is the only definitive cure for pre-eclampsia
delivery of the baby
what is the recurrence risk of pre-eclampsia
15% , rising to 50% if there is severe pre-eclampsia before 28 weeks
what are the two phenotypes for preeclampsia
early onset - complications occurs <34 weeks, foetus often growth restricted
late onset - manifests at a later gestation, no foetal growth restriction however foetal death and damage may occur
how do you classify hypertension in pre-eclampsia
Mild = 140-149/90-99
Moderate = 150-159/100-109
Severe = >160/110
how do you classify pre-eclampsia
early (<34 weeks, IUGR) or late (>34 weeks, no IUGR)
mild-moderate pre-eclampsia = no severe HTN, symptoms or biological/haematological impairment
severe = Severe hypertension +/- symptoms/biological/haemotological impairment
what is the pathophysiology of pre-eclampsia
1st step – poor placental perfusion
In normal pregnancy, trophoblast invasion of spiral arterioles (branches of the ovarian/uterine artery) leads to vasodilation of vessel walls to allow adequate placenta perfusion
In early onset PE this is incomplete causing oxidative stress, which is detected as high resistance flow in uterine arteries In late onset PE as growth of a normal placenta reaches its limits, intervillous perfusion may reduce because terminals become overcrowded causing oxidative stress
2nd step
Both mechanisms produce oxidative stress, causing the placenta to oversecrete proteins that regulate angiogenic balance
This can be detected by an increased sFlt-1 (similar to VEGF) and reduced PIGF (placental growth factor) levels in the maternal blood
Widespread endothelial damage follows, causing vasoconstriction, increased vascular permeability and clotting dysfunction – causing the clinical manifestations
what are risk factors for pre-eclampsia
Nulliparity
Family history
Previous history of PE
Long interpregnancy interval
Obesity
Extremes of maternal age (>40)
Disorders characterised by microvascular disease
Pregnancies with a large placenta
what are examples of disease characterised by microvascular disease
Chronic hypertension
Chronic renal disease
Sickle cell disease
Diabetes
Autoimmune disease
Antiphospholipid syndrome
what pregnancies are associated with a large placenta
Twins
Foetal hydrops
Molar pregnancy
what are clinical features of pre-eclampsia
Asymptomatic
Headache
Drowsiness
Visual disturbance
Nausea-vomiting
Epigastric pain (later stage)
Hypertension (often 1st sign)
Presence of epigastric tenderness is suggestive of impending complications
what are the maternal complications of pre-eclampsia
Eclampsia
Cerebrovascular haemorrhage
liver/coagulation problems - HELLP syndrome/DIC/liver failure
Renal Failure
Pulmonary Oedema
what is eclampsia
Grand mal seizure resulting from cerebrovascular vasospasm
Mortality may occur from hypoxia
what is the treatment/prophylaxis for eclampsia
Magnesium Sulphate and intensive surveillance
What is HELLP syndrome
Haemolysis
Elevated liver enxymes
Low platelets
what are the foetal complciations of pre-eclampsia
Perinatal mortality and morbidity of the foetus are increased, pre-eclampsia accounts for about 5% of still births and 10% of preterm deliveries
Early onset mainly has the issue of growth restriction, preterm delivery is often required, although spontaneous preterm labour is also more common
At term, pre-eclampsia affects foetal growth less, but it is still associated with increased morbidity and mortality, as at all gestations there is an increased risk of placental abruption
how should you investigate ?pre-eclampsia
Urine dipstick -For protein
+ve = quantification for P:Cr and total 24hr protiein
>30mg/nmol for P:Cr or >0.3g/24hr total protein is abnormal
Bloods Elevated uric acid High Hb Rapid fall in platelets Indicates HELLP DIC Rise in LFTs (Raised ALT is most indicative) Raised lactate Renal function will be impaired
USS
Estimated foetal weight at early gestations to assess foetal growth
Umbilical artery doppler is also used to estimated foetal wellbeing
Cardiotocography
what are early predictors of pre-eclampsia
Uterine artery doppler at 20 weeks - about 40% sensitive
what are late haemotological predictors of pre-eclampsia
Ratio of SFlt-1:PIGF in maternal blood later in pregnancy
Especially those with mild hypertension
what medical prevention for pre-eclampsia is recommended
Low dose aspirin (75mg) before 16 weeks reduces the risk of pre-eclampsia – NICE recommended
High dose vitamin D with calcium supplementation might also be effective
how do you manage pre-eclampsia
Women with new hypertension >140/90 are assessed in day assessment unit
SFlt-1:PIGF ratio assays determine who is at higher risk
Patients without proteinuria and with mild/moderate hypertension are usually managed as outpatients with BP/urinalysis repeated 2 per week
USS 2-4 weeks unless suggestive of foetal compromise
what is the admission criteria for pre-eclampsia
Necessary with severe hypertension and presence of proeinuria
If HTN is absent but there is significant proteinuria they should be admitted
SFlt-1:PIGFassay may determine which women are most at risk and should be admitted
what hypertensive medication is recommended for pre-eclampsia
Labetalol maintenance (alternatives = nifedipine/hydralazine)
IV if acute
what medication is given for eclampsia
Magnesium Sulfate
IV loading dose followed by IV infusion
how should you manage a severe deterioration in pre-eclampsia
IV labetalol
Magnesium sulfate
Steroids if baby is <34 weeks
Delivery ASAP
when is hypertensive therapy given in pre-eclampsia
> 150/100 (moderate)
when should a woman with pre-eclampsia deliver by
36 weeks
when is maternal pushing discouraged in labour
if they are hypertensive >160/100
how do you treat pre-eclampsia post birth
BP is highest 3-4 days after birth
1st line – beta blocker
2nd line – nefedipine + Ace-I
Tx may be needed for severeal weeks
what patient population is pre-existing hypertension common in during pregnancy
Obesity
Diabete s
Renal disease
Phaecytochroma
Cushings
Cardiac disease
Coarctation
in pre-existing hypertension in pregnancy, what medication is recommended
ACE-is should be removed as theyre teratogenic
labetalol 1st line
nifedipine 2nd line
meds may not be required in 2nd trimester due to drop in BP
what extra management is required in patients with pre-existing hypertension
low dose aspirin uterine doppler scanning exta visits (consultant care)
