Hypertensive Disorders In Pregnancy Flashcards
What are hypertensive Disorders
Hypertensive disorders of pregnancy include chronic hypertension, preeclampsia/eclampsia, gestational hypertension, and hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome.
DEFINITION HPT
HYPERTENSION
A diastolic blood pressure ≥ 90 mmHg but < 110 mmHg on two occasions, taken at least 2 hours apart, or a single diastolic measurement
of ≥ 110 mmHg
AND/OR
A systolic blood pressure ≥ 140 mmHg but <160 mmHg on two occasions, taken at least 2 hours apart, or a single systolic measurement of ≥ 160
mmHg. A raised systolic pressure is indicative of hypertension - even in the absence of a raised diastolic blood pressure.
Acute severe Hypertension
A medical emergency and is defined as a systolic BP ≥ 160 mmHg and/or diastolic BP≥110 mmHg.
Significant proteinuria
The presence of 1+ or more proteinuria on a test strip (dipstick) in a clean catch urine specimen on 2 occasions, at least 2 hours apart. Test for
proteinuria in all antenatal patients using bed side tests.
Hypertension may be accompanied by any of the following:
- The presence of 1+ or more proteinuria on a test strip (dipstick) in a clean catch urine specimen on 2 occasions, at least 2 hours apart.
- Generalized oedema of face, fingers, feet
- Eclamptic fits
- Complications such as HELLP syndrome, pulmonary edema and acute renal failure.
Classification
- Chronic hypertension
- Gestational hypertension
- Preeclampsia
- Eclampsia
Chronic hypertension?
Hypertension that is present before 20 weeks of gestation or if the woman was already taking antihypertensive medication before the pregnancy.
Gestational Hypertension?
New onset of hypertension presenting only after 20 weeks of gestation without significant proteinuria.
Pre-eclampsia?
Pre-eclampsia
Hypertension with significant proteinuria developing for the first time after 20 weeks of gestation.
Pre-eclampsia can also be superimposed on chronic hypertension - evidenced by the new onset of persistent proteinuria in a woman who had an initial diagnosis of chronic hypertension.
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Mild to moderate and preeclampsia?
• Mild to moderate and preeclampsia : a diastolic BP of 90-109 mmHg and/or systolic blood pressures of 140-159 mmHg, with ≥1+ proteinuria; and no organ dysfunction.
Severe pre-eclampsia?
• Severe pre-eclampsia:
○ Acute severe hypertension (diastolic BP of ≥110 mmHg and/or systolic of greater than 160 mm Hg) with ≥1+ proteinuria
OR
○ Hypertension and/or proteinuria (any degree) with signs of organ dysfunction (platelets <100 000/µl; creatinine or liver enzymes (ALT)
more than double the normal values; or neurological signs like persistent headache, visual disturbances and dizziness
Imminent eclampsia?
Symptoms and signs that characterise severe pre-eclamptic women, i.e. severe persistent headache, visual disturbances, epigastric pain, hyper-reflexia, clonus, dizziness and fainting, or vomiting.
Eclampsia?
Generalised tonic-clonic seizures after 20 weeks of pregnancy and within 7 days after delivery, associated with hypertension and proteinuria.
HELLP syndrome
The presence of Haemolysis, Elevated Liver enzymes and Low Platelets, almost always in association with hypertension and proteinuria.
HOW TO TAKE BLOOD PRESSURE IN PREGNANY
- Use correct cuff size (length of 1.5 times the circumference of the arm).
- Use obese cuff (15x33 cm) if the middle upper arm circumference is > 33 cm.
- Patient may sit or lie on her side – never flat on her back!
- Cuff should be on the level of the heart during measurement.
• Measure the diastolic blood pressure at the point where the sounds disappear (Korotkoff phase five). In patients
where the sounds do not disappear, use the point of muffling (Korotkoff phase four).
WOMEN AT RISK FOR THE DEVELOPMENT OF Pre-eclampsia?
ANY pregnant women CAN develop pre-eclampsia. Those most susceptible are:
- Primigravidae, in particular teenagers and elderly primigravidae
- Women of age 35 years and above
- Women with a previous pregnancy complicated by pre-eclampsia
- Women with a previous abruptio placentae or intra-uterine death.
- Women with multiple pregnancies
• Medical complications such as chronic hypertension, renal disorders, diabetes, connective tissue disorders or
antiphospholipid syndrome
• Women who develop oedema in the mid trimester or have excessive weight gain
Pathophysiology of Hypertension in pregnancy
° Weak trophoblast differentiation during the process of endothelial invasion.
°Abnormal development and remodeling of spiral arteries in the deep myometrial tissues.
°Placental hypoperfusion and ischemia
°Cascade of inflammatory events with Placental release of cytokines factors.
°Disrupting the balance of angiogenic factors and including Platelet aggregation
°Systemic endothelial dysfunction
°Decreased renal pressures natriuresis
°Systemic hypertension
Preeclampsia pathophysiology
Defective spiral artery remodeling → placental hypoperfusion → systemic vasoconstriction and endothelial dysfunction → hypertension → proteinuria and/or end-organ damage.
HELPP syndrome pathophysiology
HELLP is an extension of preeclampsia
° May be closely related to atypical hemolytic uremic syndrome
° Endothelial injury with fibrin deposits → thrombotic microangiopathy → microangiopathic hemolytic anemia (MAHA) + liver damage + platelet-activation and consumption → thrombocytopenia + elevated liver enzymes
Eclampsia
° Seizures are thought to be caused by cerebral vasospasm and cerebral edema.
° Hypertensive encephalopathy may also play a role.
Clinical Presentation for Chronic hypertension
°Asymptomatic
°Systolic BP > 140 mm Hg and/or diastolic BP > 90 mm Hg
°Begins before the 20th week of gestation
°Often preexisting
°No proteinuria
°No end-organ damage
Clinical Presentation in Gestational hypertension
° Asymptomatic
° Systolic BP > 140 mm Hg and/or diastolic BP > 90 mm Hg
° Begins after the 20th week of gestation
° No history of preexisting hypertension
° No proteinuria
° No end-organ damage
Clinical Presentation for Preeclampsia
- Occurs between 20 weeks of gestation and up to 6 weeks postpartum.
- Gestational hypertension with either proteinuria or end-organ damage
- Very common among critically ill pregnant women.
4.Cerebral symptoms
° Severe headache
° Altered mental status
5. Visual symptoms ° Scotomata ° Photophobia ° Blurred vision °Temporary blindness
- Pulmonary edema
° Dyspnea
° Rales - Renal impairment with peripheral edema
- Hepatic impairment with RUQ pain.
Eclampsia clinical presentation
- Preeclampsia with the presence of seizures
Other symptoms: ° Persistent occipital or frontal headaches ° Blurred vision ° Photophobia ° Epigastric or RUQ pain ° Altered mental status
HELLP syndrome clinical presentation
Manifestation of preeclampsia (not a separate disorder).
- Preeclampsia symptoms (proteinuria and/or end-organ damage) plus:
Hemolysis
- Pallor
- Malaise
ElevatedLiver enzymes
- RUQ pain
- Nausea and vomiting
LowPlatelets
May cause hepatic hematoma that ruptures → hemoperitoneum
General Measures for Chronic Hypertension
GENERAL MEASURES
Lifestyle Modification
- No alcohol should be taken.
- Regular moderate exercise, e.g. 30 minutes brisk walking at least 3 times a week.
- Smoking cessation.
- Aim to keep BP < 140/90 mmHg.
- Screen for end-organ damage.
- Fetal surveillance by symphysis-fundus height (SFH) growth.
- Ask mother about fetal movements at each antenatal visit.
Consider labour induction if:
BP persistently 160/110 mmHg, or
pregnancy of ≥ 38 weeks duration, or
in the presence of maternal or fetal compromise, e.g. poor SFH growth and oligohydramnios, etc.
Medicine treatment for chronic hypertension
See prevention and treatment of pre-eclampsia.
Switch ACE-inhibitors and diuretics to methyldopa and/or amlodipine. Women should be advised that there’s an increased risk of congenital abnormalities if ACE-inhibitors were taken during pregnancy.
Why are ACE-inhibitors contraindications in pregnancy
Their use during pregnancy is associated with more miscarriages and intrauterine deaths.
Why are Beta-blockers contraindications in pregnancy
Cause poor fetal growth, poor response to stress during labour and neonatal hypoglycemia.
Antenatal care in chronic hypertension
From 6 weeks’ gestation onwards, preferably before 16 weeks gestation:
1.Aspirin, oral, 150 mg daily.
LoEI [16]
- Calcium, oral.
° For high-risk patients: Calcium carbonate, oral, 500 mg 12 hourly (equivalent to 1 g elemental calcium daily).
° Although the benefit is greatest in high-risk women, consider use of this agent in all pregnant women.
° When using iron together with calcium supplementation, ensure that iron and calcium are taken at least 4 hours apart from one another
Maternal features of severe disease in pre-eclampsia:
Acute severe hypertension (diastolic BP of 110 mmHg and/or systolic >160 mmHg).
Thrombocytopenia (platelet <100 000/μL).
° Impaired liver function (ALT or AST >40 IU/L).
° Severe persistent right upper quadrant or epigastric pain.
° HELLP syndrome (platelets <100 000 and AST >70 µl and LDH >600 µl).
° Serum creatinine ≥120 micromol/L.
° Pulmonary oedema.
° New-onset severe headache unresponsive to medication.
° Visual disturbances.
Antihypertensives therapy
Antihypertensive
Medicine treatment will be dictated by blood pressure response.
Monitor progress until a stable result is achieved.
In general, diuretics are contra-indicated for hypertension in pregnant women.
When needed, combine drugs using lower doses when BP >160/100 mmHg, before increasing single medication doses to a maximum.
LoEIII [11]
° Methyldopa, oral, 250 mg 8 hourly as a starting dose.
Increase to a maximum of 750 mg 8 hourly, according to response .
LoEIII [12]
AND/OR
° Amlodipine, oral, 5 mg daily.
Increase to 10 mg daily.
Hypertensive Emergency:
SBP ≥160 mmHg and/or DBP ≥110 mmHg. Admit to a high-care setting for close monitoring.
° Nifedipine, oral, 10 mg.
° Repeat after 30 minutes if needed, until systolic blood pressure <160 mmHg and diastolic blood pressure < 110 mmHg.
° Swallow whole. Do not chew, bite or give sublingually.
Hypertensive Emergency if unable to take oral or inadequate response:
- Labetalol, IV infusion, 2 mg/minute to a total of 1–2 mg/kg.
- Reconstitute solution as follows:
° Discard 40mL of sodium chloride 0.9% from a 200 mL container.
°Add 2 vials (2 x 100 mg) of labetalol (5 mg/mL) to the remaining 160 mL of sodium chloride 0.9% to create a solution of 1 mg/mL.
° Start at 40mL/hour to a maximum of 160 mL/hour.
° Titrate against BP – aim for BP of 140/100 mmHg.
° Once hypertensive crisis has been resolved, switch to an oral preparation.
Mechanism of action for Methyldopa (Aldomet, MSD)
Alpha 2 agonist→ decreased
central adrenergic activity → resulting decrease in
vasoconstriction
Side effects of Methyldopa
° Sedation ° Depression ° Nightmares ° Dry mouth ° Nasal congestion ° Salt and water retention
Side effects of Methyldopa
° Sedation ° Depression ° Nightmares ° Dry mouth ° Nasal congestion ° Salt and water retention
Contraindications for Methyldopa
Acute hepatitis
What advise is given to women who have HTN wanting to get pregnant?
If they are taking ACE inhibitors or ARBs it can increase the risk of congenital abnormalities
same goes for thiazide or thiazide like diuretics
which women at high risk of pre-eclampsia?
- hypertensive disease during a previous pregnancy
- chronic kidney disease
- autoimmune disease such as systemic lupus erythematosus or antiphospholipid syndrome
- type 1 or type 2 diabetes
- chronic hypertension
if women is at high risk of preclampsia what medication is given as precautionary and when?
° 75-150 mg of aspirin1 daily from 12 weeks until the birth of the baby.
° if they have one high risk factor
° if they have more than one moderate risk factor
moderate risk of factors of pre-eclampsia
- first pregnancy
- age 40 years or older
- pregnancy interval of more than 10 years
- BMI of 35 kg/m2 or more at first visit
- family history of pre-eclampsia
multi-fetal pregnancy.
what test can be done to rule out pre-eclampsia between 20 weeks and up to 35 weeks of pregnancy
PIGF placetnal growth factor
what lifestyle and diet advise can be given to the pregnant woman
° weight management
° exercise
° healthy eating
° lowering the amount of salt in their diet.
what additional fetal monitoring is done in women with chronic HTN and when
ultrasound for fetal growth and amniotic fluid volume assessment, and umbilical artery doppler velocimetry at 28 weeks, 32 weeks and 36 weeks.
which women need additional fetal monitoring
- severe pre-eclampsia
- pre-eclampsia that resulted in birth before 34 weeks
- pre-eclampsia with a baby whose birth weight was less than the 10th centile
- Hx of intrauterine death
- placental abruption.
during labour when do you measure BP HTN women
hourly, in women with hypertension
every 15-30 minutes until blood pressure is less than 160/110 mmHg in women with severe hypertension.
what advise to give if women choses to breastfeed while taking antihypertensives
Consider monitoring the blood pressure of babies, especially those born preterm, who have symptoms of low blood pressure for the first few weeks
When discharged home, advise women to monitor their babies for drowsiness, lethargy, pallor, cold peripheries or poor feeding
