Hypertension in Pregnancy Flashcards
Baseline % risk of PET in a well woman with no RFs
2-3% low risk multips
Risk of PET with antiphosholipid syndrome
8x background risk. 2x9 = 18%
Risk of PET with nulliparous women
3-5%
List different classes of hypertension in pregnancy
Pre-existing hypertension (white coat, chronic, essential - when ruled out other causes)
Gestational hypertension
Pre-eclampsia
Causes of pre-existing hypertension
White coat
Essential - no other cause found
Other medical - renal (renal artery stenosis, glomerulonephritis, polycystic kidneys), cardiac (aortic co-arctation), endocrine (hyperparathyroidism, cushing’s, conn’s, phaeochromocytoma)
Investigations for other causes of hypertension (renal, cardiac, endocrine)
Renal - USS, creatinine U+Es, baseline PCR, urine for casts
Cardiac - echocardiogram, L and R arm BPs
Endocrine - hyperparathyroidism (parathyroid hormone, Ca, Phos), Cushing’s (cortisol - early morning/24h), Conn’s (renin/aldosterine ratio - affected by pregnancy however), Phaeo (plasma metanephrines)
Definition of hypertension
Systolic BP equal/greater than 140 and/or diastolic BP equal/greater than 90, on 2 or more occasions at least 4h apart …. OR one episode of severe hypertension = systolic equal/greater than 160 or diastolic equal/greater than 110
When should gestational HTN resolve by postpartum?
3 months - if elevated at this point then defined as chronic hypertension
Can a women be hypertensive with PET 6 weeks postpartum?
Yes
When should gestational HTN resolve by postpartum?
3 months - if elevated at this point then defined as chronic hypertension
Definition of PET
Gestational HTN: and evidence of end organ dysfunction - haematological Hb Plt DIC, biochemical Creat/LFTs/proteinuria/oliguria, neurological eclampsia/stroke, placental SGA/IUGR/abruption
Pre-existing HTN: and TWO other criteria of end-organ dysfunction
Visual/neurological symptoms of PET, and where in the brain does this affect?
Altered mental status, photopsia, persistent visual
scotomata, cortical blindness, retinal vasospasm
Occipital lobe
Pre-existing HTN risks
PET - 25%, 46% if severe HTN
Preterm delivery - 15% if no PET, 50% if PET
SGA - 27% if not PET, 48% if PET
CS - 44% if no PET, 70% if PET
Placental abruption
Gestational HTN - risk of PET if diagnosed at <30 weeks vs at 38 weeks
a) 40% vs b) 7%
Risk factors for PET
Age > 40 - 2 x BMI > 30 - 2 x Family history - 3 x Primip - 2-3 x Multiple pregnancy -32 x Previous PET - 7 x Long birth interval - 2-3 x if > 10 years
Pre-existing HTN , renal disease, diabetes, antiphospholipid syndrome
(10x), connective tissue disease, sickle cell disease
Rare presentations of PET <20 weeks include
Consider if hydatidiform mole, tripoloidy,
multiple pregnancy, severe renal disease or antiphospholipid syndrome
Timing of eclampsia (ante/intra/postpartum)
Antepartum (45%), intrapartum (20%), postpartum (35%).
Only 1/3 of women with eclampsia have a diagnosis of PET preceding eclapsia
40% of eclamptic fits are after delivery!
Note treat all pregnant women with seizures as though they have eclampsia, however remember it is not the most common cause of seizures
Other differentials for a seizure/possible eclamptic fit in a pregnant woman
Epilepsy, pseudoseizure, stroke, intracranial bleed (burst aneurysm, or post assault) intracranial mass, severe electrolyte disturbance (e.g. hyponatraemia)
Methyldopa - max dose, onset of action, side effects and contraindications
750mg QID (3g/day), 6h onset, drowsiness and low mood, contraindications depression/concurrent MAOI use/postpartum
Labetalol - max dose, onset/peak effect, side effects and contraindications
Varies - 300mg QID, 400mg QID, up to maximum of 2.4g/day - however recommend not to max out to prevent saturation of beta receptors.
Peak effect 2-4h.
SE bronchospasm. Beware in brittle asthma, Raynaud’s disease, phaeo
Nifedipine - max dose, onset/peak effect, side effects and contraindications
30mg BD. Long acting onset 3-4h, short acting 30-45 min.
SE - headache
Contraindications/cautions - worsening pre-existing headaches, short acting can cause large drops in BP - recommend to be on CTG
Prazosin - max dose, onset/peak effect, side effects and contraindications
4th line - consult with obs med. Start at 0.5mg daily/nocte. Can cause abrupt drop in BP esp postural, sx dizziness
IV labetalol - dose, onset of action, repeat dosing
Labetalol - 20mg IV as a bolus over 2 min, 5 min maximal onset of action
Repeat 15 mins. If still > 160/110,
given 40mg IV
Repeat in 15 mins. If still > 160/110, give 80mg IV over 2 mins.
Max 300mg.
Infusion 20-160mg/hr.
Give in ED/HDU/MCA setting, not on ward. Consider arterial line
IV hydralazine - dose, onset of action, repeat dosing
5-10mg IV bolus over 3-10min, onset of action 20 min. Repeat every 20 mins if BP remains >160/110. Max 30mg
Give in ED/HDU/MCA setting, not on ward. Consider arterial line
Why are ACE-i contraindicated in pregnancy
Second and third trimester - oligohydramnios, renal failure, bony malformations
Is an eclamptic fit an indication for immediate delivery?
NO
Stabilise the mother (MgSO4, transfer to MCCA/HDU, antihypertensives, bloods)
Stabilise the baby (steroids if preterm, MgSO4 if <30 weeks)
Discuss with the Obstetric and Obs Med SMOs re: timing of delivery
Remember to consider other differentials for seizure