Hypertension in Pregnancy

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Hypertension in Pregnancy

• Dr.Elwassiela Salih MD
• Obstetrician Gynecologist Reproductive
  Endocrinologist
• Chief of the Department
• College of Medicine
• Taif University

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OBJECTIVES

• Be able to define hypertension in relationship to
  pregnancy
• Be able to classify hypertensive diseases in
  pregnant women
• Be able to list criteria for the diagnosis of
  preeclampsia
• Be able to list criteria for the diagnosis of
  severe preeclampsia/HELLP syndrome
• Be able to discuss current management
  considerations
• Understand and discuss the effects of
  hypertension on the mother and fetus

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Hypertension

• Sustained BP elevation of 140/90 or greater
• Measurement taken while seated
• Arm at the level of the heart

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Hypertensive Disease Associated with Pregnancy

• Chronic Hypertension
• Gestational Hypertension
• Preeclampsia
• Eclampsia
• HEELP Syndrome

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Hypertensive Disease Associated with Pregnancy

• Chronic Hypertension
• Diagnosed before the 20th week or present before
  the pregnancy
• Gestational Hypertension
• Preeclampsia
• Eclampsia
• HEELP Syndrome

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Hypertensive Disease Associated with Pregnancy

• Chronic Hypertension
• Gestational Hypertension
• Criteria
• Develops after 20 weeks of gestation
• Proteinuria is absent
• Blood pressures return to normal postpartum
• Morbidity is directly related to the degree of
  hypertension
• Preeclampsia
• Eclampsia
• HEELP Syndrome

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Overlap/Disease Progression
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Hypertensive Disease Associated with Pregnancy

• Chronic Hypertension
• Gestational Hypertension
• Preeclampsia
• Criteria
• Develops after 20 weeks
• Blood pressure elevated on two occasions at least
  6 hours apart
• Associated with proteinuria and edema
• May occur less than 20 weeks with gestational
  trophoblastic neoplasia
• Eclampsia
• HEELP Syndrome

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Preeclampsia vs. Severe Preeclampsia

• Criteria for Preeclampsia

• Criteria for Severe Preclampsia

• Previously normotensive woman
• gt 140 mmHg systolic
• gt 90 mmHg diastolic
• Proteinuria gt 300 mg in 24 hour collection
• Nondependent edema

• BP gt 160 systolic or gt110 diastolic
• gt 5 gr of protein in 24 hour urine or gt 3 on 2
  dipstick urines greater than 4 hours apart
• Oliguria lt 500 mL in 24 hours
• Cerebral or visual distrubances (headache,
  scotomata)
• Pulmonary edema or cyanosis
• Epigastric or RUQ pain
• Evidence of hepatic dysfunction
• Thrombocytopenia
• Intrauterine growth restriciton (IUGR)

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Risk Factors for Preeclampsia

• Nulliparity
• Multifetal gestations
• Maternal age over 35
• Preeclampsia in a previous pregnancy
• Chronic hypertension
• Pregestational diabetes

• Vascular and connective tissue disorders
• Nephropathy
• Antiphospholipid syndrome
• Obesity
• African-American race

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Risk Factors
FACTOR RISK RATIO
Nulliparity 31
Age gt 40 31
African American 1.51
Chronic hypertension 101
Renal disease 201
Antiphospholipid syndrome 101
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Hypertensive Disease Associated with Pregnancy

• Chronic Hypertension
• Gestational Hypertension
• Preeclampsia
• Eclampsia
• Diagnosis of preeclampsia
• Presence of convulsions not explained by a
  neurologic disorder
• Grand mal seizure activity
• Occurs in 0.5 to 4 or patients with preeclampsia
• HEELP Syndrome

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Hypertensive Disease Associated with Pregnancy

• Chronic Hypertension
• Gestational Hypertension
• Preeclampsia
• Eclampsia
• HELLP Syndrome
• A distinct clinical entity with
• Hemolysis, Elevated Liver enzymes, Low Platelets
• Occurs in 4 to 12 of patients with severe
  preeclampsia
• Microangiopathic hemolysis
• Thrombocytopenia
• Hepatocellular dysfunction

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Morbidity and Mortality from Hypertensive Disease

• Hypertension affects 12 to 22 of pregnant
  patients
• Hypertensive disease is directly responsible for
  approximately 20 of maternal mortality in the
  United State

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Pathophysiology

• Vasospasm
• Uterine vessels
• Hemostasis
• Prostanoid balance
• Endothelium-derived factors
• Lipid peroxide, free radicals and antioxidants

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Pathophysiology

• Vasospasm
• Predominant finding in gestational hypertension
  and preeclampsia
• Uterine vessels
• Hemostasis
• Prostanoid balance
• Endothelium-derived factors
• Lipid peroxide, free radicals and antioxidants

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Pathophysiology

• Vasospasm
• Uterine vessels
• Inadequate maternal vascular response to
  trophoblastic mediated vascular changes
• Endothelial damage
• Hemostasis
• Prostanoid balance
• Endothelium-derived factors
• Lipid peroxide, free radicals and antioxidants

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Pathophysiology

• Vasospasm
• Uterine vessels
• Hemostasis
• Increase platelet activation resulting in
  consumption
• Increased endothelial fibronectin levels
• Decreased antithrombin III and a2-antiplasmin
  levels
• Allows for microthrombi development with
  resultant increase in endothelial damage
• Prostanoid balance
• Endothelium-derived factors
• Lipid peroxide, free radicals and antioxidants

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Pathophysiology

• Vasospasm
• Uterine vessels
• Hemostasis
• Prostanoid balance
• Prostacyclin (PGI2)Thromboxane (TXA2) balance
  shifted to favor TXA2
• TXA2 promotes
• Vasoconstriction
• Platelet aggregation
• Endothelium-derived factors
• Lipid peroxide, free radicals and antioxidants

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Pathophysiology

• Vasospasm
• Uterine vessels
• Hemostasis
• Prostanoid balance
• Endothelium-derived factors
• Nitric oxide is decreased in patients with
  preeclampsia
• As this is a vasodilator, this may result in
  vasoconstriction
• Lipid peroxide, free radicals and antioxidants

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Pathophysiology

• Vasospasm
• Uterine vessels
• Hemostasis
• Prostanoid balance
• Endothelium-derived factors
• Lipid peroxide, free radicals and antioxidants
• Increased in preeclampsia
• Have been implicated in vascular injury

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Pathophysiologic Changes

• Cardiovascular effects
• Hematologic effects
• Neurologic effects
• Pulmonary effects
• Renal effects
• Fetal effects

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Pathophysiologic Changes

• Cardiovascular effects
• Hypertension
• Increased cardiac output
• Increased systemic vascular resistance
• Hematologic effects
• Neurologic effects
• Pulmonary effects
• Renal effects
• Fetal effects

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Pathophysiologic Changes

• Cardiovascular effects
• Hematologic effects
• Volume contraction/Hypovolemia
• Elevated hematocrit
• Thrombocytopeniz
• Microangiopathic hemolytic anemia
• Third spacing of fluid
• Low oncotic pressure
• Neurologic effects
• Pulmonary effects
• Renal effects
• Fetal effects

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Pathophysiologic Changes

• Cardiovascular effects
• Hematologic effects
• Neurologic effects
• Hyperreflexia
• Headache
• Cerebral edema
• Seizures
• Pulmonary effects
• Renal effects
• Fetal effects

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Pathophysiologic Changes

• Cardiovascular effects
• Hematologic effects
• Neurologic effects
• Pulmonary effects
• Capillary leak
• Reduced colloid osmotic pressure
• Pulmonary edema
• Renal effects
• Fetal effects

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Pathophysiologic Changes

• Cardiovascular effects
• Hematologic effects
• Neurologic effects
• Pulmonary effects
• Renal effects
• Decreased glomerular filtration rate
• Glomerular endotheliosis
• Proteinuria
• Oliguria
• Acute tubular necrosis
• Fetal effects

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Renal Effects

• Decreased glomerular filtration rate
• Glomerular endotheliosis
• Proteinuria
• Oliguria
• Acute tubular necrosis

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Pathophysiologic Changes

• Cardiovascular effects
• Hematologic effects
• Neurologic effects
• Pulmonary effects
• Renal effects
• Fetal effects
• Placental abruption
• Fetal growth restriction
• Oligohydramnios
• Fetal distress
• Increased perinatal morbidity and mortality

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Management

• The ultimate cure is delivery
• Assess gestational age
• Assess cervix
• Fetal well-being
• Laboratory assessment
• Rule out severe disease!!

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Gestational HTN at Term

• Delivery is always a reasonable option if term
• If cervix is unfavorable and maternal disease is
  mild, expectant management with close observation
  is possible

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Mild Gestational HTN not at Term

• Rule out severe disease
• Conservative management
• Serial labs
• Twice weekly visits
• Antenatal fetal surveillance
• Outpatient versus inpatient

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Indications for Delivery

• Worsening BP
• Nonreassuring fetal condition
• Development of severe PIH
• Fetal lung maturity
• Favorable cervix

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Unfavorable Cervix

• No contraindication to prostaglandin agents
• If lt 32 weeks, consider cesarean
• When favorable, oxytocin

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Hypertensive Emergencies

• Fetal monitoring
• IV access
• IV hydration
• The reason to treat is maternal, not fetal
• May require ICU

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Criteria for Treatment

• Diastolic BP gt 105-110
• Systolic BP gt 200
• Avoid rapid reduction in BP
• Do not attempt to normalize BP
• Goal is DBP lt 105 not lt 90
• May precipitate fetal distress

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Characteristics of Severe HTN

• Crises are associated with hypovolemia
• Clinical assessment of hydration is inaccurate
• Unprotected vascular beds are at risk, eg, uterine

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Acute Medical Therapy

• Hydralazine
• Labetalol
• Nifedipine
• Aldomet

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Hydralazine

• Dose 5-10 mg every 20 minutes
• Onset 10-20 minutes
• Duration 3-8 hours
• Side effects headache, flushing, tachycardia,
  lupus like symptoms
• Mechanism peripheral vasodilator

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Labetalol

• Dose 20mg, then 40, then 80 every 20 minutes,
  for a total of 220mg
• Onset 1-2 minutes
• Duration 6-16 hours
• Side effects hypotension
• Mechanism Alpha and Beta block

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Nifedipine

• Dose 10 mg po, not sublingual
• Onset 5-10 minutes
• Duration 4-8 hours
• Side effects chest pain, headache, tachycardia
• Mechanism CA channel block

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Seizure Prophylaxis

• Magnesium sulfate
• 4-6 g bolus
• 1-2 g/hour
• Monitor urine output and DTRs
• With renal dysfunction, may require a lower dose

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Magnesium Sulfate

• Is not a hypotensive agent
• Works as a centrally acting anticonvulsant
• Also blocks neuromuscular conduction
• Serum levels 6-8 mg/dL

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Toxicity

• Respiratory rate lt 12
• DTRs not detectable
• Altered sensorium
• Urine output lt 25-30 cc/hour
• Antidote 10 ml of 10 solution of calcium
  gluconate 1 v over 3 minutes

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Treatment of Eclampsia

• Few people die of seizures
• Protect patient
• Avoid insertion of airways and padded tongue
  blades
• IV access
• MGSO4 4-6 bolus, if not effective, give another 2
  g

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Alternate Anticonvulsants

• Have not been shown to be as efficacious as
  magnesium sulfate and may result in sedation that
  makes evaluation of the patient more difficult
• Diazepam 5-10 mg IV
• Sodium Amytal 100 mg IV
• Pentobarbital 125 mg IV
• Dilantin 500-1000 mg IV infusion

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After the Seizure

• Assess maternal labs
• Fetal well-being
• Effect delivery
• Transport when indicated
• No need for immediate cesarean delivery

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Other Complications

• Pulmonary edema
• Oliguria
• Persistent hypertension
• DIC

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HELLP Syndrome

• He-hemolysis
• EL-elevated liver enzymes
• LP-low platelets

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HELLP Syndrome

• Is a variant of severe preeclampsia
• Platelets lt 100,000
• LFTs - 2 x normal
• May occur against a background of what appears to
  be mild disease

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Conservative Management

• Controversial
• Steroids
• Requires tertiary care
• Must have stable labs and reassuring fetal status
• May use antihypertensives

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Prevention

• Low dose ASA ineffective in patients at low risk
• Calcium supplementation is ineffective (2.0 g of
  calcium gluconate per day)
• No compelling evidence that either are harmful
• Recent study done with antioxidant (1,000mg VitC
  and 400mg VitE).
• Small study that needs to be confirmed.

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SUMMARY

• Criteria for diagnosis
• Laboratory and fetal assessment
• Magnesium sulfate seizure prophylaxis
• Timing and place of delivery