Post on 14-Aug-2015
Objectives
• To define the different hypertensive disorders of pregnancy
• To identify the diagnostic criteria of these disorders
• To briefly discuss their pathophysiology• To determine the appropriate
management of each disorders
Hypertension• Systolic BP ≥ 140mmHg or Diastolic BP ≥ 90mmHg
Proteinuria• ≥ 300mg protein per 24-hour urine collection• urine protein : creatinine ratio ≥ 0.3• or persistent 30 mg/dL (1+ dipstick) protein in
random urine samples
Chronic Hypertension
• BP ≥ 140/90 mm Hg before pregnancy or diagnosed before 20 weeks’ gestation not attributable to gestational trophoblastic disease
OR• Hypertension first diagnosed after 20
weeks’ gestation and persistent after 12 weeks postpartum
Chronic Hypertension
Before Pregnancy
Pregnancy
After Pregnancy
20 weeks of pregnancy
12 weeks after pregnancy
Chronic Hypertension
Caused by:• Essential Hypertension• Secondary to other medical conditions (ie: renal
disease)
Gestational Hypertension
• Hypertension for first time during pregnancy
• No proteinuria• BP normalize before 12 weeks postpartum• Final diagnosis made only postpartum• May have other signs or symptoms of
preeclampsia, for example, epigastric discomfort or thrombocytopenia
Gestational Hypertension
Risk Factors• maternal factors
• Primigravida (80-90% of gestational Hypertension)• First conception with a new partner• PMHx or FHx of gestational HTN• DM, chronic HTN, or renal insufficiency• Antiphospholipid syndrome• Extremes of maternal age (<18 or >35 yr)
• fetal factors• IUGR or oligohydramnios, multiple gestation, fetal hydrops• Previous stillbirth or intrauterine fetal demise
Chronic and Gestational HypertensionManagement• Labetalol 100-300 mg PO BID/TID; nifedipine, 30-
50 mg PO daily or α-methyldopa 250-500 mg PO TID/QID
• no ACE inhibitors, diuretics or propanolol (teratogens)
Preeclampsia
• BP ≥ 140/90 mm Hg after 20 weeks’ gestation
• Proteinuria ≥ 300 mg/24 hours or ≥ 1 + dipstick
Preeclampsia
• Increased certainty• BP ≥ 160/110 mm Hg• Proteinuria 2.0 g/24 hours or ≥ 2+ dipstick• Serum creatinine ≥ 1.2 mg/dL unless known to be
previously elevated• Platelets < 100,000/μL• Microangiopathic hemolysis—increased LDH• Elevated serum transaminase levels—ALT or AST• Persistent headache or other cerebral or visual disturbance• Persistent epigastric pain
Eclampsia
• Preeclampsia + Seizure• Cannot be attributed to other causes in a
woman with preeclampsia• Generalized Tonic – Clonic Seizure• Designated as antepartum, intrapartum,
postpartum depending on the onset of convulsion
• Common on the 3rd trimester
Incidence and Risk Factor
• Incidence: 5 - 10% (wide variation)
• Influence by• Parity, race, ethnicity, genetic predisposition
• Nulliparous• Total:7.6% and severe: 3.3% (Hauth, 2000)
• Risk factor• Chronic hypertension, multifetal gestation, maternal old age (>35
yrs), obesity, African-American ethnicity
Williams Obstetric 22 edition, Chapter 34: Hypertensive Disorders in Pregnancy
Incidence and Risk Factor
BMI (Kg/m2) Morbidity (%)
<19.8 4.3
>35 13.3
Gestation
twin 13
single 5
• Maternal weight and the risk of preeclampsia is progressive.
• Smoking during pregnancy reduced risk of hypertension during pregnancy (Bainbridge,2005 ; Zhang, 1999)
• Placenta previa also reduced the risk of hypertensionWilliams Obstetric 22 edition, Chapter 34: Hypertensive Disorders in Pregnancy
Pathogenesis
Abnormal Trophoblastic Invasion
• Abnormally narrow spiral arteriolar lumen
• Impaired placental blood flow
• Hypoxia• Release of placental
factors
Pathophysiology
Abnormal Trophoblastic Invasion
Immunological maladaptive tolerance
between maternal,paternal (placental), and
fetal tissues
Maternal maladaptation to cardiovascular or
inflammatory changes of normal pregnancy
Genetic factors including inherited predisposing
genes.
Pathophysiology
Inflammatory changes
• Release of cytokines (TNF-α, IL)
• ↑ ROS and free radicals• Injury to endothelial cell
Pathophysiology
Endothelial Cell Activation
• Vasospasm• Activation of Microvascular
coagulation (Thrombocytopenia)
• ↑ Capillary Permeability
Pathophysiology
Cardiovascular System
• Decrease cardiac output• Decrease plasma volume• Increase natriuretic factor• Pulmonary edema• Increase systemic vascular
resistance• Increase blood pressure• Increase angiotensin II sensitivity
Pathophysiology
Renal System
• Proteinuria• Decrease glomerular filtration rate →
increase creatinine• Decrease renal blood floe• Decrease urinary sodium, uric acid,
and calcium excretion• Decrease plasma renin activity
Pathophysiology
Hemodynamic
• Decrease blood volume compare to normal pregnancy
• Vasoconstriction and increase endothelial permeability.
• Hemoconcentration is usually not as marked.
Pathophysiology
Coagulation and platelet
• Thrombocytopenia• Severe disease: < 100,000/uL• Platelet count continues to decrease
→ indication of delivery →the platelet count increases progressively after delivery (within 3 to 5 day)
• HELLP syndrome: hemolysis, elevated liver enzymes, and low platelets
Pathophysiology
Liver
• Periportal hemorrhagic necrosis in the periphery of the liver lobule
• RUQ or mid-epigastric pain and tenderness
• Serum liver enzyme is elevated – AST and ALT
• Hepatic hematoma (may rupture)
Pathophysiology
Brain
• Gross intracerebral hemorrhage – 60% (fetal in half)
• Headache, visual symptoms, convulsions, behavioral changes
Placental Perfusion/Vascular Resistance-Related Tests (Provocative Pressor Tests)“Roll-over test”• measures the hypertensive response in women at 28 to 32 week• resting in the left lateral decubitus position• then “roll over” to assume a supine position
Isometric Exercise Test• employs the same principle by squeezing a handball
Angiotensin II Infusion Test• giving incrementally increasing doses intravenously,• hypertensive response is quantified
sensitivities of all three tests to range from 55 to 70 percent withspecificities of approximately 85 percent
Placental Perfusion/Vascular Resistance-Related Tests (Uterine Artery Doppler Velocimetry)
Doppler ultrasound in the first or mid trimesterIncreased uterine artery velocimetry Provide indirect evidence of abnormal placental implantation
Renal Dysfunction-Related Tests
Serum Uric Acid• ↓ glomerular filtration, ↑ tubular reabsorption, ↓ secretion
• reduced uric acid clearance• ensitivity ranged from 0 to 55 percent and specificity
from 77 to 95 percent
Endothelial Dysfunction and OxidantStress-Related Tests• Fibronectins• Coagulation Activation• Thrombocytopenia and platelet dysfunction
• Oxidative Stress• Increased levels of lipid peroxides with decreased
antioxidant activity
Dietary Manipulation
Low-Salt Diet• Ineffective in preventing preeclampsia
Calcium Supplementation• Low dietary calcium intake were at significantly
increased risk for gestational hypertension • Unless women are calcium deficient,
supplementation has no salutary effects
Low dose Aspirin
• Suppression of platelet thromboxane synthesis
• Sparing of endothelial prostacyclin production
• Studies have shown no beneficial effect on preeclampsia
Antioxidants
• Thus antioxidants have shown to be elevated on preeclampsia
• Antioxidants have no effect
Basic management
• Termination of Pregnancy with the least possible trauma to mother and fetus
• Birth of an infant who subsequently thrives
• Complete restoration of health of mother
Prenatal Surveillance
• Until 28 weeks – prenatal every 4 weeks• >28 weeks to 36 weeks – every 2 weeks• > 36 weeks – every week• For early detection of preeclampsia
• Women with hypertension are frequently admitted for 2 to 3 days to evaluate severity of new-onset pregnancy hypertension
• Diastolic BP 81 -89 or sudden weight gain (>2lb per week) – return visits every 2-4 days
Hospitalization
• For persistent or worsening hypertension or development of proteinuria
• Evaluation:• Detailed examination followed by daily scrutiny for
clinical findings such as headache, visual disturbance, epigastric pain, and rapid weight gain
• Daily weight monitoring• Analysis for proteinuria every 2 days• BP monitoring in sitting position every 4 hours, except
between midnight and morning
Hospitalization
• Measurements of plasma or serum creatinine, hematocrit, platelets and serum liver enzymes – frequency to be determined by severity of hypertension
• Frequent evaluation of fetal size and amniotic fluid volume
• Reduce physical activity throughout much of the day
• Ample protein and calories on diet• Sodium and fluid intake should not be limited
or forced
Hospitalization
• Measurements of plasma or serum creatinine, hematocrit, platelets and serum liver enzymes – frequency to be determined by severity of hypertension
• Frequent evaluation of fetal size and amniotic fluid volume
• Reduce physical activity throughout much of the day
• Ample protein and calories on diet• Sodium and fluid intake should not be limited
or forced
Home Health Care
• Mild-to-moderate hypertension and without proteinuria
• Reduce physical activities• Home BP and urine protein monitoring
Home Health Care
• Mild-to-moderate hypertension and without proteinuria
• Reduce physical activities• Home BP and urine protein monitoring
Termination of Pregnancy
• Delivery is the cure for preeclampsia• Headache, visual disturbance, epigastric pain or
oliguria indicate that convulsions are imminent• Anticonvulsants are indicated for severe
preeclampsia• Moderate or severe preeclampsia that does not
improve hospitalization, delivery is advisable• Induced by IV oxytocin• Preinduction cervical ripening – prostaglandin or osmotic dilator
• CS indicated for more severe preeclampsia
Clinical Features
• Seizures may be violent• Typically lasting 60-75 s• One of the signs of an impending seizure is hyperreflxia• Symptoms that may occur before the seizure include
persistent frontal or occipital headache, blurred vision, photophobia, right upper quadrant or epigastric pain, and altered mental status
• Upto one third of cases, there is no proteinuria or hypertension prior to the seizure
• After seizure usually postictal, but in some, coma may follow
Management (Major Component)
• Control of convulsion• Control of hypertension• Avoidance of diuretics unless with
pulmonary edema; limitation of IVF unless with severe blood loss; avoidance of hyperosmotic agents
• Delivery
Control of convulsion
• Magnesium Sulfate as IV/IM• Given during labor and for 24 hours postpartum• Schedule (Continuous IV infusion):• Loading dose: 4 to 6 g diluted in 100mL IVF over 15-20 mins• Begin 2 g/hr in 30mL IV maintenance infusion• Measure serum magnesium level at 4-6 hr and adjust
infusion to maintain levels between 4 and 7 mEq/L (4.8-8.4 mg/dL)
• Discontinued 24hr after delivery
Antihypertensive Therapy
Hydralazine• IV if SBP ≥160mmHg or DBP ≥110mmHg• 5 to 10 mg doses at q15 to 20mins until stable (DBP: 90-
100)• More effective than labetalol
Labetalol• IV, more rapid and associated tachycardia is minimal• 10mg IV initially, not stable in 10mins? then 20mg is given• Not stable in 10mins? Give 40mg
Antihypertensive Therapy
Hydralazine• IV if SBP ≥160mmHg or DBP ≥110mmHg• 5 to 10 mg doses at q15 to 20mins until stable (DBP: 90-
100)• More effective than labetalol
Labetalol• IV, more rapid and associated tachycardia is minimal• 10mg IV initially, not stable in 10mins? then 20mg is given• Not stable in 10mins? Give 40mg
Intravenous Fluid Therapy
Lactated Ringer solution is administered routinely at the rate of 60 to 125mL per hour unless indicated