Hypertensive disease in pregnancy (incl. pre-eclampsia and eclampsia) Flashcards
Define hypertension in pregnancy including the differences between the 3 types.
Hypertension in pregnancy in usually defined as:
- systolic > 140 mmHg or diastolic > 90 mmHg
- OR an increase above booking readings of > 30 mmHg systolic or > 15 mmHg diastolic
Types:
- Chronic = hx of HTN before pregnancy or BP >140/90mmHg at <20 weeks
- Gestational = HTN as above occurring at >20 weeks
- Pre-eclampsia = HTN at >20 weeks and proteinuria >0.3g/24hours
What is chronic hypertension?
Hypertension present before 20 weeks
How common is pre-existing hypertension in pregnancy?
3-5% affected, more common in older women
Why might chronic hypertension be masked in the first trimester?
There is a phsyiological decrease in BP here
What is the management of chronic (pre-existing) hypertension pre-conception?
Adjust medication:
Stop ACEi, ARBs, thiazides and thiazide-like diuretics
Arrange alternatives with GP within 2 days of +ve pregnancy test
- Labetalol (1st line)
- Nifedipine (2nd)
What is the antenatal management of chronic hypertension?
Conservative - give lifestyle advice on exercise, diet and salt intake
Monitoring -
- BP weekly if poorly controlled otherwise 2-4 weekly
- serial growth scans 4-weekly at 28-36 weeks
Medical -
- Low dose aspirin 75mg OD from 12 weeks gestation until birth
Which antihypertensives must be stopped before pregnancy or as soon as possible after and why?
ACE inhibitors, ARBs, thiazide or thiazide-like diuretics cause congenital malformations if taken early during the pregnancy
Other antihypertensives have shown no such association
What is the goal BP in HTN management in pregnancy?
135/85 mmHg
Why is aspirin given antenatally in chronic hypertension patients?
It is used as an anti-platelet medication as chronic hypertension is a “high risk” factor for pre-eclampsia
NB: 1 high risk factor or 2 or more moderate risk factors = give aspirin
How often should antenatal appointments be given to monitor HTN in pregnancy?
- weekly appointments if hypertension is poorly controlled
- appointments every 2 to 4 weeks if hypertension is well-controlled.
Should induction of labour be offered in chronic HTN?
If <160/110mmHg after 37 weeks then patient and senior obstetrician can decide on time of birth. These patients do not need to be induced at a specific time.
What is the postnatal management of chronic HTN post-partum?
BP monitoring - daily for first 2 days after birth, then at least once between day 3-5, as clinically indicated once medication is changed after birth.
Follow up at 2 weeks with GP or specialist for antihypertensive review to enzure BP <140/90mmHg
Offer women with chronic hypertension a medical review 6–8 weeks after the birth with their GP or specialist as appropriate.
What is gestational hypertension?
New HTN without proteinuria occurring after 20 weeks gestation
What proportion of women with gestational hypertension progress to pre-eclampsia?
a third
Are there any adverse outcomes associated with gestational hypertension?
Benign condition so no
But may progress to pre-eclamspia
What is the difference in management of a gestational HTN patient with BP:
- 140/90-159/109mmHg?
- >160/110mmHg?
NB: PLGF offerred at 20-35 weeks only
What is the management of gestational hypertension antenatally?
Antenatal - consider admission to antenatal ward if severe (>160/110 mmHg) until BP is controlled
Monitoring -
- BP and urinalysis 1-2x/week until BP is controlled, thereafter weekly
- Bloods (FBC, LFTs, U&Es) weekly
- US foetal surveillance (growth, liquor, UA blood flow) every 2-4 weeks
- PlGF-based testing on 1 occasion if suspicion of pre-eclampsia
Medical - antihypertensives
- 1st line = labetalol
- 2nd line = nifedipine
- 3rd line = methyldopa
Aim for BP <135/85 mmHg
What is the postnatal management of gestational hypertension?
Monitoring BP - daily for first 2 days, at least once between days 3-5 and then as clinically indicated if antihypertensive treatment is changed after birth
Medical - continue treatment if required (NB: stop methyldopa within 2 days postnatally and change to alternative agent). Reduce medication if BP falls to <130/80 mmHg.
Follow up -
- At 2 weeks at GP if still on antihypertensive treatment
- At 6-8 weeks i. with GP or specialist; if fails to resolve consider diagnosis of chronic hypertension
If a patient did not take anti-HTN treatment for gestational hypertension but postnatally has a BP of 155/100mmHg, should you start treatment then?
For women with gestational hypertension who did not take antihypertensive treatment and have given birth, start antihypertensive treatment if their BP is 150/100 mmHg or higher
How long is gestational hypertension expected to last postnatally?
When should you think about reducing the treatment?
Duration of postnatal anti-HTN treatment will usually be similar to duratio of antenatal treatment (but may be longer)
Reduce if BP <130/80mmHg
Define pre-eclampsia.
New HTN with proteinuria occurring after 20 weeks gestation
Apart from ‘new onset HTN after 20 weeks’ what are the other 3 major factors which are used in pre-eclampsia diagnosis?
New onset of hypertension (>140 mmHg systolic or >90 mmHg diastolic) >20 weeks pregnancy and the coexistence of 1 or more of the following new-onset conditions:
- proteinuria (urine protein:creatinine ratio of 30 mg/mmol or more or albumin:creatinine ratio of 8 mg/mmol or more, or at least 1 g/litre [2+] on dipstick testing) or
- other maternal organ dysfunction
- uteroplacental dysfunction such as fetal growth restriction, abnormal umbilical artery doppler waveform analysis, or stillbirth.
Give 4 examples of ‘maternal organ dysfunction’ which can be used in the diagnosis of pre-eclampsia.
- Renal insufficiency - Cr _>_90 micromol/L, _>_1.02 mg/100 ml
- Liver involvement - elevated transaminases [ALT or AST >40 IU/L] +/- RUQ or epigastric abdominal pain
- Neurological complications - such as eclampsia, altered mental status, blindness, stroke, clonus, severe headaches or persistent visual scotomata
- Haematological complications - such as thrombocytopenia (Plt <150,000/microlitre), DIC or haemolysis
Which test can be used to rule out pre-eclampsia early between 20-35 weeks of pregnancy?
If women with chronic hypertension are suspected of developing pre-eclampsia
offer placental growth factor (PlGF)-based testing
to help rule out pre-eclampsia between 20 weeks and up to 35 weeks
What are the differences in management of pre-eclampsia with normal vs severe hypertension?
What is the ABCDE approach for eclampsia?
What is the pathophysiology of pre-eclampsia?
Only occurs in pregnancy, but also reported where there is placenta but no fetus e.g. molar pregnancy - suggests that trophoblast tissue is a stimulus
Theory is that development of pre-eclamsia has 2 stages:
- Stage 1: Trophoblast invasion is patchy and spiral arteries retain their muscular walls. This prevents development of high-flow, low impedance uteroplacental ciruclation and leads to uteroplacental ischaemia. Why trophoblasts invade less effectively is unknown but may be to do with maternal immune system
- Stage 2: Uteroplacental ischaemia results in oxidative and inflammatory stress, with the invovlement of secondary mediators leading to endothelial dysfunction, vasospasm and activation of coagulation. The target cell (endothelial) is so ubiquitous that pre-eclampsia is truly a multisystem disorder affecting many organs concurrently.
