hypertensive in pregnancy

Hypertensive in PregnancyAlcaraz, Adrian F.

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

Definition of Terms

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

Hypertensive Disorders of Pregnancy

Chronic Hypertension

Gestational Hypertension

Preeclampsia

Eclampsia


• 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


Before Pregnancy

Pregnancy

After Pregnancy

20 weeks of pregnancy

12 weeks after pregnancy


Caused by:• Essential Hypertension• Secondary to other medical conditions (ie: renal

disease)


• 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


Before Pregnancy Pregnancy After Pregnancy

12 weeks after pregnancy


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

Preeclampsia

Before Pregnancy

Pregnancy

After Pregnancy


+ Proteinuria

Preeclampsia

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

Eclampsia

Before Pregnancy

Pregnancy

After Pregnancy


+ Proteinuria+ Seizure

Risk Factor

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

Pathogenesis

Abnormal Trophoblastic Invasion

• Abnormally narrow spiral arteriolar lumen

• Impaired placental blood flow

• Hypoxia• Release of placental

factors

Pathophysiology

Abnormal Trophoblastic

Invasion

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

Preeclampsia• Edema• Proteinuria

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

Predictive

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

Prevention

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

Management (Preeclampsia)

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

Preterm Pregnancy with PreeclampsiaGlucocorticoids• enhance lung maturation

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

Eclampsia

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

Control of convulsion

• Schedule (Intermittent IM injections):

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

Thank you

hypertensive in pregnancy

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