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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>