Hypertension in Pregnancy

Prof \ Refaat Al-Sheimy

Hypertension in PregnancyIntroduction

• Complicates 7-10% of pregnancies

– 70% Preeclampsia-eclampsia

– 30% Chronic hypertension

• Eclampsia 0.05% incidence

• 20% of Maternal Deaths

• Cause of 10% of Preterm birth

• Etiology unknown

Hypertension in PregnancyIntroduction

• Young female 3 fold increased risk• African American 2 fold increased risk• Multifetal pregnancies

– Twins– Triplets

• Hypertension• Renal Disease• Collagen Vascular Disease

Hypertension in PregnancyClassification

• Chronic hypertension

• Preeclampsia-eclampsia

• Preeclampsia Superimposed upon chronic hypertension or Renal Disease

• Gestational hypertension (only during pregnancy)

• Transient hypertension (only after pregnancy)

Chronic Hypertension

Defined as hypertension diagnosed

• Before pregnancy

• Before the 20th week of gestation

• During pregnancy and not resolved postpartum

Gestational Hypertension

• Gestational Hypertension:

– Systolic >140

– Diastolic>90

– No Proteinurea

– 25% Develop Pre-eclampsia

Gestational Hypertension

Diagnosis of gestational hypertension:• Detected for first time after midpregnancy• No proteinuria• Only until a more specific diagnosis can be assigned

postpartum

If preeclampsia does not develop and • BP returns to normal by 12 weeks postpartum, diagnosis is

transient hypertension. • BP remains high postpartum, diagnosis is chronic

hypertension.• Proteinurea develops Preeclampsia is diagnosed (25%

incidence)

Preeclampsia-Eclampsia

• Occurs after 20th week (earlier with trophoblastic disease)

• Increased BP (gestational BP elevation) with proteinuria

• Edema is NOT part of this definition

Diagnosis of Preeclampsia-Eclampsia

• Gestational Hypertension:

– Systolic >140

– Diastolic>90• Proteinuria is defined as urinary

excretion– 0.3 g protein or greater in a 24-hour– +2 or greater on urine dip specimen

Preeclampsia-Eclampsia• Blood pressure

• Measure blood pressure in the sitting position, with the cuff at the level of the heart. Inferior vena caval compression by the gravid uterus while the patient is supine can alter readings substantially, leading to an underestimation of the blood pressure. Blood pressures measured in the left lateral position similarly may yield falsely low values if the blood pressure is measured in the higher arm and the cuff is not maintained at heart level.

• Allow women to sit quietly for 5-10 minutes before measuring the blood pressure.

Preeclampsia-Eclampsia

• Blood pressure• Record Korotkoff sounds I (the first sound)

and V (the disappearance of sound) to denote the systolic blood pressure (SPB) and DPB, respectively. In about 5% of women, an exaggerated gap exists between the fourth (muffling) and fifth (disappearance) Korotkoff sounds, with the fifth sound approaching zero. In this setting, record both the fourth and fifth sounds (eg, 120/80/40 with sound I = 120, sound IV = 80, sound V = 40).

Classification of Preeclampsia-Eclampsia

• Mild Pre-eclampsia• Severe Pre-eclampsia

Classification of Preeclampsia-Eclampsia

• Criteria for Severe Preeclampsia (one or more)– Blood Pressure: >160 systolic, >110 diastolic

– Proteinurea: >5gm in 24 hours, over 3+ urine dip

– Oligurea: less than 400ml in 24 hours

– CNS: Visual changes, headache, scotomata, mental status change

– Pulmonary Edema

– Epigastric or RUQ Pain: Usually indicates liver involvement

Classification of Preeclampsia-Eclampsia

• Criteria for Severe Preeclampsia (one or more)– Impaired Liver Function tests

– Thrombocytopenia: >100,000

– Intrauterine Growth Restriction: With or without abnormal doppler assessment

– Oligohydramnios

Classification of Preeclampsia Superimposed Upon Chronic

HypertensionHypertension and no proteinuria < 20 weeks:

New-onset proteinuria after 20 weeks

Hypertension and proteinuria < 20 weeks:• Sudden increase in proteinuria• Sudden increase in BP in women whose

hypertension was well controlled• Thrombocytopenia (platelet count <100,000

cells/mm3)• Increase in ALT or AST to abnormal levels

Clinical Implications of Preeclampsia

• Preeclampsia ranges from mild to severe.• Progression may be slow or rapid – hours

to days to weeks.

For clinical management, preeclampsia should be over diagnosed to prevent maternal and perinatal morbidity and mortality – primarily through timing of delivery.

Pathophysiology

Of importance, and distinguishing preeclampsia from chronic or gestational hypertension, is that preeclampsia is more than hypertension; it is a systemic syndrome, and several of its “nonhypertensive” complications can be life-threatening when blood pressure elevations are quite mild.

Pathophysiology

The maternal disease is characterized by

• Vasospasm• Activation of the coagulation system• Perturbations in humoral and autacoid systems

related to volume and blood pressure control• Oxidative stress and inflammatory-like responses• Pathologic changes that are ischemic in nature

Pathophysiology

Heart: Generally unaffected; cardiac decompensation in the presence of preexisting heart disease.

Kidney: Renal lesions (glomerular endotheliosis); GFR and renal blood flow decrease; hyperuricemia; proteinuria may appear late in clinical course; hypocalciuria; alterations in calcium regulatory hormones; impaired sodium excretion; suppression of renin angiotensin system.

Pathophysiology

Coagulation System: Thrombocytopenia; low antithrombin III; higher fibronectin.

Liver: HELLP syndrome (hemolysis, elevated ALT and AST, and low platelet count).

CNS: Eclampsia is the convulsive phase of preeclampsia. Symptoms may include headache and visual disturbances, including blurred vision, scotomata, and, rarely, cortical blindness.

Symptoms of Preeclampsia • Visual disturbances typical of preeclampsia are

scintillations and scotomata. These disturbances are presumed to be due to cerebral vasospasm.

• Headache is of new onset and may be described as frontal, throbbing, or similar to a migraine headache. However, no classic headache of preeclampsia exists.

• Epigastric pain is due to hepatic swelling and inflammation, with stretch of the liver capsule. Pain may be of sudden onset, it may be constant, and it may be moderate-to-severe in intensity.

Symptoms of preeclampsia

• While mild lower extremity edema is common in normal pregnancy, rapidly increasing or nondependent edema may be a signal of developing preeclampsia. However, this signal theory remains controversial and recently has been removed from most criteria for the diagnosis of preeclampsia.

• Rapid weight gain is a result of edema due to capillary leak as well as renal sodium and fluid retention.

Physical Findings in Preeclampsia

• Blood Pressure

• Proteinurea

• Retinal vasospasm or Retinal edema

• Right upper quadrant (RUQ) abdominal tenderness stems from liver swelling and capsular stretch

Physical findings in Preeclampsia

– Brisk, or hyperactive, reflexes are common during pregnancy, but clonus is a sign of neuromuscular irritability that raises concern.

– Among pregnant women, 30% have some lower extremity edema as part of their normal pregnancy. However, a sudden change in dependent edema, edema in nondependent areas such as the face and hands, or rapid weight gain suggests a pathologic process and warrants further evaluation

Differential Diagnosis

• Documentation of HBP before conception or before gestational week 20 favors a diagnosis of chronic hypertension (essential or secondary).

• HBP presenting at midpregnancy (weeks 20 to 28) may be due to early preeclampsia, transient hypertension, or unrecognized chronic hypertension.

Differential Diagnosis

• Thrombotic Thrombocytopenic Purpura (TTP)

• Hemolytic Uremic Syndrome (HUS)

• Acute Fatty Liver of Pregnancy (AFLP)

Laboratory Tests

High-risk patients presenting with normal BP:

• Hematocrit • Hemoglobin• Serum uric acid• If 1+ protein by routine urinalysis (clean catch)

present obtain a timed collection for protein and creatinine

• Accurate dating and assessment of fetal growth• Baseline sonogram at 25 to 28 weeks

Laboratory Tests

Patients presenting with hypertension before gestation week 20:

• Same tests as described for high-risk patients presenting with normal BP

• Early baseline sonography for dating and fetal size

Laboratory Tests

Patients presenting with hypertension after midpregnancy:

• Quantification of protein excretion

• Hemoglobin and hematocrit and platelet count

• Serum creatinine, uric acid, and transaminase level

• Serum albumin, LDH, blood smear, and coagulation profile

Preeclampsia: Treatment

• Goal is to prevent eclampsia and other severe complications.

• Attempts to treat preeclampsia by natriuresis or by lowering BP may exacerbate pathologic changes.

• Palliate maternal condition to allow fetal maturation and cervical ripening.

Preeclampsia: Treatment

• Maternal Evaluation• Goals:• Early recognition of preeclampsia • Observe progression, both to prevent maternal

complications and protect well-being of fetus. Early signs:

• BP rises in late second and early third trimesters.

• Initial appearance of proteinuria is important.

Preeclampsia: Treatment

• Maternal Evaluation (cont.)• Often, hospitalization recommended with new-

onset preeclampsia to assess maternal and fetal conditions.

• Hospitalization for duration of pregnancy indicated for preterm onset of severe gestational hypertension or preeclampsia.

• Ambulatory management at home or at day-care unit may be considered with mild gestational hypertension or preeclampsia remote from term

Preeclampsia

Preeclampsia

• Antepartum Management of Preeclampsia• Little to suggest therapy alters the underlying

pathophysiology of preeclampsia.

• Restricted activity may be reasonable. • Sodium restriction and diuretic therapy appear

to have no positive effect.

Preeclampsia

• Indications for Delivery in Preeclampsia* • Maternal• Gestational age 38 weeks• Platelet count < 100,000 cells/mm3• Progressive deterioration in liver and renal function• Suspected abruptio placentae• Persistent severe headaches, visual changes, nausea,

epigastric pain, or vomiting• *Delivery should be based on maternal and fetal

conditions as well as gestational age.

Preeclampsia

• Indications for Delivery in Preeclampsia* - Fetal

• Severe fetal growth restriction• Nonreassuring fetal testing results• Oligohydramnios

• *Delivery should be based on maternal and fetal conditions as well as gestational age.

Preeclampsia

• The “cure” for preeclampsia is delivery– The “cure” is always beneficial for the

mother, although c-section might be needed– The “cure” may be deleterious for the fetus

Preeclampsia

• Route of Delivery• Vaginal delivery is preferable.• Aggressive labor induction (within 24 hours).• Neuraxial (epidural, spinal, and combined

spinal-epidural) techniques offer advantages.• Hydralazine, nitroglycerin, or labetalol may be

used as pretreatment to reduce significant hypertension during delivery.

Preeclampsia

• Anticonvulsive Therapy• Indicated to prevent recurrent

convulsions in women with eclampsia or to prevent convulsions in women with preeclampsia.

• Parenteral magnesium sulfate reduces the frequency of eclampsia and maternal death. (Caution in renal failure.)

Treatment of Acute Severe Hypertension in Pregnancy

• SBP > 160 mm Hg and/or DBP > 105 mm Hg• Parenteral hydralazine is most commonly

used.• Parenteral labetalol is second-line drug (avoid

in women with asthma and CHF.)• Oral nifedipine used with caution. (Short-

acting nifedipine is not approved by FDA for managing hypertension.)

• Sodium nitroprusside may be used in rare cases.

Postpartum Counseling and Followup

• Counseling for Future Pregnancies

• Risk of recurrent preeclampsia increases with• Preeclampsia before 30 weeks (40%)• Multiparas as compared with nulliparas or new

father• Risk of recurrent preeclampsia may be

substantially greater in African Americans.

Remote Prognosis

• Preeclampsia-Eclampsia• The more certain the diagnosis of

preeclampsia, the lower the prevalence of remote cardiovascular disorders.

• Preeclampsia-eclampsia in subsequent pregnancies helps define future risk.

• Gestational hypertension in any pregnancy increases remote cardiovascular risk.