Blood Pressure in Pregnancy Flashcards
(31 cards)
How does blood pressure fluctuate throughout pregnancy?
Blood pressure changes in a normal and characteristic way during pregnancy
Reduced, at the start due to reduced vascular resistance from the effects of progesterone
Increased, after 24 weeks due to increase in stroke volume
Decreased after delivery but may peak 3-4 days post-partum
What are the cut off values for hypertension in pregnancy?
Mild 140-149 systolic, 90-99 diastolic
Moderate 150-159 systolic 100-109 diastolic
Severe >160 systolic > 110 diastolic
What is pregnancy induced hypertension?
Gestational hypertension or pregnancy induced hypertension = new onset hypertension diagnosed after 20 weeks without significant proteinuria or an increase above booking readings of > 30 mmHg systolic or > 15 mmHg diastolic. Both increase risk of PET.
What is the definition for pre-existing hypertension?
A history of hypertension before pregnancy or an elevated blood pressure > 140/90 mmHg before 20 weeks gestation
No proteinuria, no oedema
What is the definition of pre eclampsia?
Pregnancy-induced hypertension in association with proteinuria (> 0.3g / 24 hours)
Oedema may occur but is now less commonly used as a criteria.
How should pre existing hypertension be managed during pregnancy?
Prior to conception (Essential/Chronic Hypertension)
• Need to be changed to a pregnancy friendly drug i.e. Labetalol
• Aspirin daily from 12 weeks to reduce risk of pre-eclampsia
• Growth pathway – increased risk of growth restriction
• Consultant lead care
• Smoking, diet weight, alcohol advice etc.
• Induced around due date
How should pregnancy induced hypertension be managed?
- Aspirin daily to reduce risk of pre-eclampsia (depends on risk factors) if one high or two or more moderate risk factors for pre-eclampsia
- Delivery aimed for EDD
- Medication to treat hypertension
What is the 1st line drug used for hypertension during pregnancy, list some common side effects and other important guidelines regarding it.
Labetalol (1st line)
Beta-blocker.
Scalp tingling, postural hypotension, fatigue, headache, nausea and vomiting, epigastric pain and liver damage.
Contraindicated in asthmatics and
DMT1 – removes palpitations which are a sign of hypos
Not effective in black, afro-Caribbean’s
What is the 2nd line drug used for hypertension during pregnancy, list some common side effects and other important guidelines regarding it.
Nifedipine (MR)
Calcium channel blocker.
Inhibition of labour, peripheral oedema, dizziness, flushing, headache, constipation.
Avoid grapefruit juice
Nifedipine always given MR unless given stat to stop contractions
What is the 3rd line drug used for hypertension during pregnancy, list some common side effects and other important guidelines regarding it.
Methyldopa
Alpha-agonist.
Depression, drowsiness, headache, oedema, GI disturbances, dry mouth, postural hypotension, bradycardia, hepatotoxicity.
Good for replacing ACE inhibitors
Avoid in severe depression and post-natally
Should ACEi be used during pregnancy?
Can they be used postnatally?
Note: ACE-inhibitors are contra-indicated in pregnancy due to their association with congenital abnormalities.
Enalapril – ACE inhibitor. Used post-natal (not first line). Side effects: dry cough, dyspnoea and depression.
Safe in breastfeeding
How would you treat a black afro-carribean lady, with asthma who’s throwing up and has severe HTN?
Hydralazine – useful in black Caribbean, asthmatic who’s throwing up with severe high BP.
Avoid in severe tachy, recent MI, idiopathic SLE or before 3rd trimester.
Side effects: tachycardia. Flushing and palpitations. IV infusion.
Safe in breastfeeding
What is pre eclampsia?
Pathophysiology – mechanism unknown. Generally considered to be due to poor placental perfusion as a result of abnormal placentation. Normally muscles around the spiral arteries are destroyed during placentation meaning they can’t constrict = healthy blood supply. In Pre-eclampsia remodelling is incomplete creating a high resistance low flow system.
The resultant BP increase combined with hypoxia and oxidative stress leads to a systemic inflammatory response and endothelial dysfunction resulting in leak blood vessels.
What are the high and moderate risk factors for PET?
High Risk
Hypertensive disease in previous pregnancy
Chronic kidney disease
Autoimmune disease e.g. lupus, antiphospholipid syndrome
Type 1 or 2 diabetes
Chronic hypertension
Moderate Risk First pregnancy Age 40 or older Pregnancy interval of more than 10 years BMI > 35 Family history of pre-eclampsia Multiple pregnancy
When should aspirin be taken to prevent PET?
If one high risk factor or 2 or more moderate, then daily Aspirin from 12 weeks gestation until birth
What are the maternal signs and symptoms of PET?
A woman greater than 20 weeks gestation
• Hypertension (140/90) on two occasions at least 4 hours apart
• Significant proteinuria >300mg in 24 hours or >30 urinary protein:creatinine (PCR)
May be asymptomatic
Visual disturbances
Headaches (usually frontal that won’t go away)
Epigastric pain/RUQ (hepatic capsule distention/infarction): comes, stays and won’t go away
Confusion
Sudden onset oedema
Uterine tenderness or vaginal bleeding from abruption
Hyper-reflexia
Urate, urea, LDH and creatinine usually raised
What are the foetal symptoms of PET?
Reduce foetal movements
IUGR
Reduced liquor
Poor dopplers
How should suspected PET be investigated?
Urine dipstick and BP, U&E and LDH
Monitor for organ dysfunction
• Mother: FBC, Urea and electrolytes, liver function tests and clotting
• Foetus: Umbilical artery doppler – look for end diastolic flow. Absent is better than reversed.
Where should PET be managed?
Once substantial proteinuria then must be admitted and have high level monitoring of both maternal and foetal well being
How should pre eclampsia be managed?
Only cure for pre-eclampsia
is delivery.
- Hypertensive treatments – aim for <160/110 – Stat PO Nifedipine every 30 mins – if BP remains high after 3 doses then IV labetalol (methyldopa if asthmatic)
- Prevention of VTE – fragmin
- Magnesium sulphate is used stat to treat eclamptic fits
- After 34 weeks gestation same day delivery may be considered
- Epidurals will help to keep blood pressure down during labour
- Strict fluid balance
- Steroids if less than 34 weeks
What are the indications for immediate delivery in a patient with PET
Indications for immediate delivery: • Worsening thrombocytopenia • Worsening liver or renal function • Severe maternal symptoms especially epigastric pain and poor LFTs • HELLP pre-eclampsia • Foetal distress
Is there any risk after delivery indicated for PET?
Still high risk of eclamptic seizures post-partum so mother should be monitored for her blood pressure often in first 2 days post-partum then at least once a day 3-5 days post-partum. Reassess need for antihypertensives after these 5 days.
What symptoms suggest a high risk of seizure and how should that be managed?
If high risk of a seizure: hyper-reflexia, symptomatic, severe hypertension, abnormal blood tests then give prophylactic magnesium sulphate IV infusion
When treating PET with magnesium sulphate what should you be aware of?
Be aware of magnesium toxicity – respiratory depression, loss of patella reflexes, confusion, weakness, flushing, sweating, bradycardias/arrhythmia – STOP Magnesium sulphate. If toxic give calcium gluconate.
