Antenatal Care: HTN & Pre-eclampsia Flashcards
In normal pregnancy, how does BP change?
1st trimester: BP usually falls (particularly the diastolic), and continues to fall until 20-24 weeks
After this: BP usually increases to pre-pregnancy levels by term
What is HTN in pregnancy defined as?
Systolic >140 mmHg or diastolic >90 mmHg
OR an increase above booking readings of > 30 mmHg systolic or > 15 mmHg diastolic
After establishing that a pregnant woman is hypertensive, she should be categorised into one of what 3 groups?
1) Pre-existing HTN
2) Pregnancy-induced HTN (gestational HTN)
3) Pre-eclampsia
Women who are at high risk of developing pre-eclampsia should take what?
Aspirin 75mg od from 12 weeks until the birth of the baby.
When should women at risk of pre-eclampsia start taking aspirin?
From 12 weeks until birth
What is pre-existing HTN in pregnancy defined as?
A history of hypertension before pregnancy or an elevated blood pressure > 140/90 mmHg before 20 weeks gestation
Who is pre-existing HTN in pregnancy more common in?
Older women
Is there proteinuria or oedema in pre-existing HTN in pregnancy?
No proteinuria, no oedema
If a woman taking an ACEi or ARB for pre-existing hypertension becomes pregnant, what should happen?
Stopped immediately and alternative antihypertensives started (e.g. labetalol) whilst awaiting specialist review
What is pregnancy-induced (gestational) HTN defined as?
HTN occurring in the second half of pregnancy (i.e. after 20 weeks)
What is cut off point for HTN being defiend as ‘pre-existing’ or ‘pregnancy-induced’?
20 weeks gestation
Is there proteinuria or oedema in pre-existing HTN in pregnancy?
No proteinuria, no oedema
What are women with gestational HTN at risk of?
Increased risk of future pre-eclampsia or hypertension later in life
How does gestational HTN resolve?
Resolves following birth (typically after one month).
What is pre-eclampsia defined as?
Pregnancy-induced hypertension in association with proteinuria (> 0.3g / 24 hours)
Is there proteinuria or oedema in pre-existing HTN in pregnancy?
Proteinuria: yes
Oedema: can occur but is now less commonly used as a criteria
What % of pregnancies does pre-eclampsia affect?
Around 5%
1st line HTN medication in pregnancy?
oral labetalol
If patient is asthmatic, 1st line medication for HTN in pregnancy?
oral nifedipine and hydralazine
What is pre-eclampsia?
Pre-eclampsia refers to new high blood pressure (hypertension) in pregnancy with end-organ dysfunction, notably with proteinuria (protein in the urine).
Key finding in pre-eclampsia?
Proteinuria
At what gestation age does pre-eclampsia occur?
After 20 weeks gestation
Pathophysiology of pre-eclampsia?
It occurs after 20 weeks gestation:
1) the spiral arteries of the placenta form abnormally,
2) this leads to a high vascular resistance in these vessels and poor perfusion of placenta
3) causes oxidative stress in the placenta, and the release of inflammatory chemicals into the systemic circulation
4) systemic inflammation and impaired endothelial function in the blood vessels.
What triad is seen in pre-eclampsia?
1) HTN
2) Proteinuria
3) Oedema
Complications of pre-eclampsia?
Pre-eclampsia is a significant cause of maternal and fetal morbidity and mortality.
- maternal organ damage
- fetal growth restriction
- seizures
- early labour
- death
What is eclampsia?
Eclampsia is when seizures occur as a result of pre-eclampsia.
Pre-eclampsia risk factors are categories into high and moderate risk factors.
What are some high risk factors for pre-eclampsia?
1) Pre-existing HTN
2) Previous HTN in pregnancy
3) Existing autoimmune conditions (e.g. SLE)
4) Diabetes (1 or 2)
5) CKD
What are some moderate risk factors for pre-eclampsia?
1) Age >40y
2) BMI >35
3) >10 years since previous pregnancy
4) Multiple pregnancy
5) First pregnancy
6) FH of pre-eclampsia
These risk factors for pre-eclampsia are used to determine which women are offered aspirin as prophylaxis.
Which women would be offered aspirin?
One high risk factor
OR
More than one moderate risk factor.
symptoms of pre-eclampsia?
Pre-eclampsia has symptoms of the complications:
- Headache
- Visual disturbance or blurriness
- Nausea and vomiting
- Upper abdominal or epigastric pain (this is due to liver swelling)
- Oedema
- Reduced urine output
- Brisk reflexes
Criteria for diagnosis of pre-eclampsia?
1) new-onset blood pressure >/= 140/90 mmHg after 20 weeks of pregnancy
AND 1 or more of the following:
a) proteinuria
b) organ dysfunction e.g. raised creatinine (creatinine ≥ 90 umol/L), elevated liver enzymes, seizures, thrombocytopenia, haemolytic anaemia
b) placental dysfunction (e.g. fetal growth restriction or abnormal Doppler studies)
Features of severe pre-eclampsia?
- hypertension: typically > 160/110 mmHg and proteinuria as above
- proteinuria: dipstick ++/+++
- headache
- visual disturbance
- papilloedema
- RUQ/epigastric pain
- hyperreflexia
- platelet count < 100 * 106/l, abnormal liver enzymes or HELLP syndrome
Potential consequences of pre-eclampsia?
Neuro:
- eclampsia
- altered mental status
- blindness
- stroke
- clonus
- severe headaches
- persistent visual scotomata
Foetal:
- intrauterine growth retardation
- prematurity
Liver involvement (elevated transaminases)
Haemorrhage:
- placental abruption
- intra-abdominal
- intra-cerebral
Cardiac failure
Using what 2 ways can proteinuria be quantified?
1) Urine protein:creatinine ratio (above 30mg/mmol is significant)
2) Urine albumin:creatinine ratio (above 8mg/mmol is significant)
What urine ACR is significant in pre-eclampsia?
above 8mg/mmol
What test is recommended in women suspected of having pre-eclampsia?
placental growth factor (PlGF) testing
what is placental growth factor?
A protein released by the placenta that functions to stimulate the development of new blood vessels.
Placental growth factor levels in pre-eclampsia?
Low
When is PlGF testing recommended?
NICE recommends using PlGF between 20 and 35 weeks gestation to rule-out pre-eclampsia.
When is aspirin given in risk of pre-eclampsia?
It is given from 12 weeks gestation until birth to women with:
a) A single high-risk factor
b) Two or more moderate-risk factors
All pregnant women are routinely monitored at every antenatal appointment for evidence of pre-eclampsia.
How are they monitored?
1) BP
2) Symptoms
3) Urine dipstick for proteinuria
When gestational hypertension (without proteinuria) is identified, what is general management?
1) Treating to aim for a blood pressure below 135/85 mmHg
2) Admission for women with a blood pressure above 160/110 mmHg
3) Urine dipstick testing at least weekly
4) Monitoring of blood tests weekly (full blood count, liver enzymes and renal profile)
5) Monitoring fetal growth by serial growth scans
6) PlGF testing on one occasion
how often is PlGF measured in potential pre-eclampsia?
Only once
What is aim of BP of women with gestational hypertension (without proteinuria)?
below 135/85 mmHg
What BP should pregnant women be admitted for?
Admission for women with a blood pressure above 160/110 mmHg
How often should urinalysis be performed in women with gestational hypertension (without proteinuria)?
Weekly
General management of pre-eclampsia?
1) emergency secondary care assessment for any woman in whom pre-eclampsia is suspected
2) BP is monitored closely (at least every 48 hours)
3) US monitoring of the fetus, amniotic fluid and dopplers is performed two weekly
What scoring system are used to determine whether to admit the woman with suspected pre-eclampsia?
fullPIERS or PREP‑S
1st line medical mangement of pre-eclampsia?
Labetolol (beta blocker)
2nd line medical mangement of pre-eclampsia?
Nifedipine
3rd line medical mangement of pre-eclampsia?
Methyldopa (needs to be stopped within two days of birth)
What may be used as an antihypertensive in critical care in severe pre-eclampsia or eclampsia?
IV hydralazine may
What may be given during labour and in the 24 hours afterwards to prevent seizures in pre-eclampsia?
IV magnesium sulphate
What may be necessary if the blood pressure cannot be controlled or complications occur in pre-eclampsia?
Planned early birth
What should be given to women having a premature birth?
Corticosteroids
Purpose of corticosteroids in premature birth?
help mature the fetal lungs.
Management of pre-eclampsia after delivery?
1) Monitor BP closely
2) BP will return to normal over time once the placenta is removed.
For medical treatment, NICE recommend after delivery switching to one or a combination of:
1) Enalapril (first-line)
2) Nifedipine or amlodipine (first-line in black African or Caribbean patients)
3) Labetolol or atenolol (third-line)
1st line medical management of pre-eclampsia AFTER delivery?
Enalapril
What is eclampsia?
Eclampsia refers to the seizures associated with pre-eclampsia
What is used to manage seizures associated with pre-eclampsia?
IV magnesium sulphate
What is HELLP syndrome?
HELLP syndrome is a combination of features that occurs as a complication of pre-eclampsia and eclampsia:
H - Haemolysis
Elevated Liver Enzymes
Low Platelets
How should fluids be managed in severe pre-eclampsia/eclampsia?
Fluid restriction to avoid the potentially serious consequences of fluid overload
Basic pathophysiology of pre-eclampsia:
Development of abnormal placenta:
1) Spiral arteries normally dilate in normal pregnancy and develop into large utero-placental arteries (can deliver lots of blood to developing foetus)
2) In pre-eclampsia - these spiral arteries become fibrous & narrow (less blood to placenta)
3) Poorly perfused placenta –> IUGR or foetal death
4) Hypoperfused placenta –> releases pro-inflammatory proteins –> get into maternal circulation –> endothelial cell dysfunction –> vasoconstriction & causes kidneys to retain more salt –> HTN
What are 2 key complications of severe pre-eclampsia (i.e. >160mmHg systolic or >110mmHg diastolic)?
1) Placental abruption
2) Haemorrhagic stroke
2 kidney features of pre-eclampsia?
1) oliguria
2) proteinuria
These are signs of glomerular damage
Eye features of pre-eclampsia? What is the cause?
Features:
- blurred vision
- flashing lights
- scotoma
Cause - reduced blood flow to retina
Liver features of pre-eclampsia? What is the cause?
Cause - reduced blood flow to liver
Features:
- hepatomegaly –> stretches capsule around liver –> causes RUQ/epigastric pain
- elevated liver enzymes
How can pre-eclampsia lead to haemolysis?
Endothelial cell injury leads to lots of tiny thrombi in microvasculature (uses up platelets).
This causes RBCs to undergo haemolysis as they pass through.
This results in HELLP syndrome.
How can pre-eclampsia cause oedema?
Endothelial injury increases vascular permeability –> oedema
Also proteinuria causes hypoalbuminaemia –> oedema
How can oedema in pre-eclampsia present?
1) Generalised oedema: legs, face & hands
2) Pulmonary oedema: cough & SOB
3) Cerebral oedema: headache, confusion & seizures
When can pre-eclampsia develop?
Can develop from 20 weeks gestation to up to 6 weeks after delivery.
What is hydralazine?
Is a direct vasodilator that can be given IV to rapidly reduce BP in hypertensive emergency.
