Hypertension in Pregnancy Flashcards
How many pregnancies will hypertension affect?
10-15%
Who is PET most likely to affect?
Primigravida
What is the commonest cause of iatrogenic prematurity?
PET
Describe the CV changes in pregnancy
Plasma vol increased by 45% CO increased by 30-50% SV increased by 25% HR increased by 15-25% PVR increased by 15-20%
How will BP change in pregnancy?
Mid pregnancy dip in 2nd trim
Progressive risk in HR
Definition of hypertension in pregnancy?
> 140/90 on 2 occasions
>160/110 once
What are the different forms of hypertension in pregnancy?
Pre-existing hypertension (PEH)
Pregnancy induced hypertension (PIH)
Pre-eclampsia (PET)
What is pre-existing hypertension?
Diagnosis prior to pregnancy
If hypertx before 20 weeks; nothing to do with baby
What are the secondary causes of PEH?
Renal/ cardiac anomalies
Cushing’s
Conn’s
Phaeo
What are the risks to PEH in pregnancy?
Double the risk of developing PET
IUGR
Abruption
When will PIH resolve?
Within 6/52 of delivery
What differentiates PIH from PET?
Hypertension with no other features such as proteinuria or pre-eclampsia
Cardinal signs of pre-eclampsia?
Hypertension
Proteinuria (>0.3 g/l or >300 mcg/24hr)
Oedema
What causes pre-eclampsia?
Diffuse vascular endothelial dysfunction with widespread circulatory disturbance
Can affect; renal/ hepatic/ CV/ haematology/ CNS/ placenta
Describe early pre-eclampsia?
<34 weeks
Assoc with extensive villous and vascular lesions of placenta
Higher risk of maternal and foetal complications that late PET
Deswcribe late PET
> 34 weeks
Minimal placental lesions
Maternal factors (metabolic syndrome and hypertx)
What is stage 1 of the pathogenesis of PET?
Abnormal placental perfusion resulting in placental ischaemia
Failure of placentation and trophoblast invasion and thinning of spiral arteries resulting in a high resistance, low flow placenta
What is stage 2 of the pathogenesis of PET?
Widespread endothelial damage and dysfunction
Endothelial activation resulting in increased capillary permeability, increased expression of CAM, increased prothrombotic factors, increased platelet aggregation, increased vasoconstriction
What is one of the central pathogenic mechanisms in pre-eclampsia?
Imbalance of angiogenic and antiangiogenic factors
Endothelial dysfunction
What symptoms can PET present with (as a multisystem disorder)?
CNS; seizures Renal; AKI Hepatic; HELLP Haematological; HELLP, DIC Pulmonary oedema CV; hypertx, cardiomyopathy Placental; insufficiency and infarction (IUGR, abruption, stillbirth)
Si and Sy of HELLP?
Epigastric/ RUQ pain
Hepatic capsule rupture -> intra-abdominal haemorrhage
Abnormal liver enzymes
What does HELLP stand for?
Haemolysis
Elevated Liver enzymes
Low Platelets
What can placental disease result in?
FGR
Placental abruption
Stillbirth - IUD
Symptoms of PET?
Headache Visual disturbance Epigastric/ RUQ pain N+V Rapidly progressive oedema
Signs of PET
Hypertx Proteinuria Oedema Abdominal tenderness Disorientation SGA IUD Hyperreflexia/ involuntary movements/ clonus
Describe a praevia vs abruption?
Praevia; painless antepartum haemorrhage
Abruption; painful antepartum haemorrhage
Ix for PET?
U+Es Serum urate = first thing to go off LFTs FBC Coag screen Protein:Creatinine ratio CTG USS; foetal assessment
Management of PET?
Assess risk at booking
Hypertension <20 weeks; look for secondary cause
Antenatal screening; BP, urine, maternal uterine artery doppler
Treat hypertension
Maternal and foetal surveillance
Timing of delivery
Risk factors for development of PET?
Maternal age over 40 Maternal BMI over 30 Family history Primi Multiple Previous PET Birth interval >10 yrs Molar/ triploidy Multiparous women will develop more severe disease
How can PET point to a diagnosis of a molar pregnancy?
If pre-eclamptic before 12 weeks; high chance of it being a molar pregnancy - esp partial (has potential to be missed on USS)
What are the medical risk factors that predispose to the development of pre-eclampsia?
Pre-existing renal disease Pre-existing hypertension Diabetes (pre or gestational) Connective tissue; SLE Thrombophilias; APS
What is the mechanism of low dose aspirin in pre-eclampsia prevention?
Inhibits cyclooxygenase and prevents TXA2 synthesis
Prevents thrombosis in placenta
When should LDA be started?
Before 16 weeks 150 mg (NICE is 75 mg)
Via what scanning method can pre-eclampsia be predicted?
Maternal uterine artery doppler at 20-24 weeks
What will be seen that can point towards pre-eclampsia on maternal uterine artery doppler?
Notch
High resistance waveform with very little flow in diastole
When should women be referred to the antenatal day care unit?
BP >140/90
++ proteinuria
++ oedema
Symptoms esp persistent headache
When should women be admitted with pre-eclampsia?
BP >170/110 or >140/90 with ++ proteinuria
Significant symptoms; headache, visual disturbance, abdo pain
Abnormal biochemistry
Significant proteinuria >300 mg/ 24 hrs
Need for antihypertensive therapy
Signs of foetal compromise; abnormal scan or CTG
What is the inpatient assessment of pre-eclampsia?
BP 4 hrly Urinalysis daily Input/ output fluid balance chart Urine PCR Bloods; FBC, U+Es, urate, LFTS minimum 2x weekly
Will treatment of hypertension alter the course of pre-eclampsia?
No; can still develop severe PET
What is the target for BP?
135/85 mmHg
Mode of action of methyldopa?
Centrally acting alpha agonist
CI to methyldopa?
Depression
Can antihypertensives be taken whilst breastfeeding?
Yes; all prescribed during pregnancy can be used whilst breastfeeding EXCEPT doxazosin
Mode of action of labetalol?
Alpha and beta antagonist
CI to labetalol?
Asthma
Mode of action of nifedipine?
Ca channel antagonist
Mode of action of hydralazine?
Vasodilator
Mode of action of doxazosin?
Alpha antagonist
What antihypertensives are CI in pregnancy and breastfeeding?
Diuretics
ACEi
How can the foetus be surveyed in PET?
Foetal movements
CTG daily
USS; biometry, amniotic fluid index, umbilical artery doppler
What abdominal circumference suggests FGR?
<10th centile
What is the amniotic fluid index a marker of?
Foetal renal function; will be reduced if the baby is sick
What is the difference between the umbilical artery doppler and uterine artery doppler?
Uterine artery; 20 weeks. Marker of PET
Umbilical artery doppler; 3rd trim investigation. Identified resistance in the placenta
What is a really worrying sign in umbilical artery doppler?
Reverse flow in diastole
What is the only cure for pre-eclampsia?
Birth
What should be given to women if they are having a preterm delivery?
Steroids; beta/dexamethasone
Decreases risk of NEC, intraventricular haemorrhage and increases production of pulmonary surfactant
Indications for birth in pre-eclampsia?
Term gestation Inability to control BP Rapidly deteriorating biochem/ haematology Eclampsia Other crisis Foetal compromise; USS or CTG
What are crises in pre-eclampsia?
Eclampsia HELLP Pulmonary oedema Placental abruption Cerebral haemorrhage Cortical blindness DIC Acute renal failure Hepatic rupture
What is eclampsia?
Tonic-clonic seizure occurring with features of pre-eclampsia
Most common in intra-post partum period
More common in teenagers
Management of severe PET/ eclampsia?
Control BP
Stop/ prevent seizures
Fluid balance
Delivery
What antihypertensives can be used in management of severe pre-eclampsia/ eclampsia?
IV labetolol
IV hydralazine
Do you need to be careful when treating BP in eclamptic mothers?
YES; if you drop it too low can cause foetal compromise
Due to diseased placenta; a high blood pressure is required for adequate flow
What is used for seizure treatment/ prophylaxis in eclampsia?
Magnesium sulphate Loading dose; 4g IV over 5 mins Maintenance; IV infusion 1g/hr If further seizures; 2g If persistent; diazepam 10mg IV
What is the most common complication leading to death in pre-eclampsia?
Pulmonary oedema; be careful with fluid balance
Run 80ml/hr
How should labour and birth be managed in pre-eclampsia?
Aim for vaginal Control BP Epidural CTG Avoid ergometrine Caution with IV fluids
Why is an epidural helpful in pre-eclamptic women in birth?
Will result in hypotension
Why should ergometrine be avoided in pre-eclamptic women?
It is a hypertensive agent
In active 3rd stage of labour; give synticonon