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Hypertension in Pregnancy

Dapinderjit Gill Ross University MS3

Hypertension

Disorders in

Pregnancy

Gestational HTN

Transient HTN of pregnancy

Preeclampsia Mild Severe

Eclampsia

Chronic HTN preceding pregnancy

Chronic HTN with superimposed pregnancy-induced hypertension Superimposed

preeclampsia Superimposed eclampsia

Classification of the American College of

Obstetricians and Gynecologists

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Gestational Hypertension

Gestational HTN

sustained systolic blood pressure at or above 140mmHg, or a diastolic blood pressure of 90mmHg or greater

increase in BP must be present on at least two separate occasions, 6 hours or more apart

HTN in late pregnancy (>20 weeks gestation) in the absence of other findings suggestive of preeclampsia

if BP returns to baseline by 12 weeks postpartum = dx. of Transient hypertension of pregnancy

Gestational HTN

5-10% of pregnancies that proceed beyond 1st trimester develop gestational HTN

increased incidence of up to 30% in multiple gestation

15-25% of women initially diagnosed with gestational HTN develop preeclampsia

Earlier onset of gestational HTN are more likely to progress to preeclampsia

PathophysiologyChanges seen in patients

Cardiovascular effects Elevated BP Increased cardiac output

Hematologic effects Third spacing of fluid due to increased blood

pressure and decreased plasma oncotic pressure

Renal effects Atheroscleroticlike changes in renal vessels

(glomerular endotheliosis) decreased glomerular filtration rate and proteinuria

Uric acid filtration is decreased

PathophysiologyChanges seen in patients

Neurologic effects Hyperreflexia/hypersensitivity (does not correlate with severity of

disease) In severe cases, grand mal seizures

Pulmonary effects Pulmonary edema may occur due

to decreased colloid oncotic pressure

Fetal effects (severe gestational HTN) Vasospasm Decreased intermittent placental perfusion IUGR,

oligohydramnios, low birth weight

PathophysiologyMechanisms

Uterine vascular changes Trophoblastic-mediated vascular changes decreased

musculature in spiral arterioles development of low resistance, low pressure, high-flow system

Inadequate maternal vascular response Endothelial damage is also noted within the vessels

Hemostatic changes Increased PLT activation with increased endothelial fibronectin

and decreased antithrombin III and alpha-2-antiplasmin further endothelial damage is thought to promote further vasospasm

PathophysiologyMechanisms

Changes in prostanoids During pregnancy, both PGI2 (vasodilation and decreased

PLT aggregation) and TXA2 (vasoconstriction and PLT aggregation) are increased with balance favored to PGI2

In preeclampsia, TXA2 is favored

Changes in endothelium-derived factors Decrease in Nitric oxide promoting

vasoconstriction

Gestational HTN

Mild: outpatient with weekly visits, bed rest

Antihypertensive therapy: Indicated if diastolic pressure is repeatedly above 110mmHg Hydralazine (Apresoline) 5mg increments IV until acceptable BP

is obtained (diastolic pressure to 90-100mmHg range) Other medications that can be used in pregnancy (oral):

methyldopa 250mg BID/TID max 3g/day Labetalol 100mg max 2400mg/day Nifedipine 30-60mg max 120mg/day

Magnesium sulfate in severe gestational HTN for seizure prophylaxis

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Chronic Hypertension

Chronic HTN

HTN present before 20th week of gestation or beyond 6 weeks postpartum (>12 weeks postpartum from uptodate.com)

15% of gestational HTN cases go on to develop chronic HTN

25% risk of developing superimposed preeclampsia or eclampsia Close monitoring of maternal BP and follow

appropriate fetal growth and well-being Pt. should be encouraged to increase the

amount of time she rests

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Preeclampsia

Preeclampsia

Development of HTN with proteinuria induced by pregnancy generally in the second half of gestation

More frequent at the extremes of reproductive years

More common in women who have not carried a previous pregnancy beyond 20 weeks

old women or young lady?

Preeclampsia

Mild: BP: systolic > 140mmHg and/or diastolic > 90mmHg Proteinuria: >300mg on 24h collection of +1 on single

sample

Severe: BP: systolic > 160-180mmHg and/or diastolic > 110mmHg Proteinuria: >5g on 24h collection or +2 on single sample Multisystem alterations: cerebral or visual disturbances,

oliguria, pulmonary edema, cyanosis, epigastric or right upper quadrant pain, thrombocytopenia

Preeclampsia

Preeclampsia

Mild preeclampsia If immature fetus bed rest mainly in

lateral decubitus position HTN therapy if needed

Severe preeclampsia Magnesium sulfate 4g loading dose with 1-3g/hr infusion rate Antihypertensive therapy Induction or cesarean delivery

fetal pulmonary maturity depending on gestational age should be considered (>=34weeks)

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Eclampsia

Eclampsia

addition of convulsions in a woman with preeclampsia

occurs in 0.5-4% of deliveries

most cases occur within 24h of delivery with about 3% of cases diagnosed between 2-10 days postpartum

25% have eclamptic seizures before labour, 50% during labour, and 25% after delivery

Eclampsia

Anticonvulsant therapy Diazepam or similar drugs

Magnesium sulfate to prevent further seizures

Maintain adequate airway, oxygenation, restraining gently as needed and inserting a padded tongue blade

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HELLP Syndrome

HELLP Syndrome

HTN patients with hemolysis (H), elevated liver enzymes (EL), low platelet count (LP)

4-12% of pt. with severe preeclampsia and eclampsia develop HELLP syndrome

first sx. often missed: nausea, emesis, and non-specific viral-like syndrome

HELLP!

HELLP Syndrome

Treatment:

cardiovascular stabilization, correction of coagulation abnormalities, and delivery

PLT transfusion before or after delivery if PLT count is <20,000/mm3 (advised at <50,000/mm3 before cesarean) <32 weeks gestation; steroid therapy may help

stabilize maternal PLT count

Thank You!

References

Beckmann, Charles R.B., Ling, Frank W., Smith, Roger P., Barzansky, Barbara M., Herbert, William N.P., Laube, Douglas W. “Obstetrics and Gynecology”. 5th edition Lippincott Williams & Wilkins. pp. 188-196

Magloire, Lissa etc. “Gestational Hypertension”. May 2011.<uptodate.com>

August, Phyllis et. al. “Management of hypertension in pregnancy and postpartum women”. May 2011 <uptodate.com>