Hypertension and Pregnancy

• Blood pressure (BP)


  Routinely decreases during pregnancy, reaching its nadir in the mid-second trimester, then slowly increases back to baseline by the third trimester
• Categories of hypertension in pregnancy

  • Chronic hypertension
  • Hypertension specific to pregnancy (gestational hypertension, preeclampsia, eclampsia)
• Chronic hypertension


  • Seen increasingly in pregnancy, associated with complications of pregnancy
• Hypertension specific to pregnancy


  • Includes gestational hypertension, preeclampsia, eclampsia
• HELLP syndrome


  Hemolysis, elevated liver enzymes, low platelets - a subcategory of preeclampsia
• Acute fatty liver of pregnancy (AFLP)

  A disorder with high morbidity and mortality, may be related to preeclamptic syndromes
• Complications from preeclampsia, HELLP, and AFLP are leading causes of maternal death and premature delivery
• Preeclampsia


  Historically diagnosed by nondependent edema, hypertension, and proteinuria, but nondependent edema is no longer a component of the diagnosis
• Preeclampsia


  • Underlying pathophysiology involves generalized arteriolar constriction and intravascular depletion, leading to vascular damage and imbalance in prostacyclin and thromboxane
• No definitive cause for preeclampsia has been determined
• Fetal complications of preeclampsia

  • Prematurity
  • Acute uteroplacental insufficiency (abruption, fetal hypoxia)
  • Chronic uteroplacental insufficiency (IUGR)
• Maternal complications of preeclampsia


  • Seizure and stroke
  • Oliguria and renal failure
  • Pulmonary edema
  • Liver edema and subcapsular hematoma
  • Thrombocytopenia and DIC
• Severe preeclampsia


  Diagnosed with severely elevated BP (SBP >160 mmHg or DBP >110 mmHg) or presence of clinical findings
• HELLP syndrome


  Uncommon but patients decline rapidly, resulting in poor maternal and fetal outcomes
• Preeclampsia occurs in 5-6% of live births, most commonly in the third trimester
• Patients with HELLP are more likely to be less than 36 weeks' gestation at presentation
• Risk factors for preeclampsia


  • Chronic hypertension
  • Renal disease
  • African American race
  • Nulliparity
  • Previous preeclampsia
  • Multiple gestation
  • Abnormal placentation
  • New paternity
  • Family history
  • Cohabitation <1 year
• Gestational hypertension (GH)


  BP elevated above 140/90 mmHg on at least two occasions, without proteinuria
• Mild preeclampsia


  Third-trimester BP >140/90 mmHg, proteinuria >300 mg/24 hours
• Severe preeclampsia


  BP >160/110 mmHg, proteinuria >5 g/24 hours, or presence of severe signs/symptoms
• HELLP syndrome


  Rapidly deteriorating liver function and thrombocytopenia, often with DIC
• Acute fatty liver of pregnancy (AFLP)


  Unclear if in spectrum of preeclamptic syndromes or separate entity, presents with liver failure
• Acute Fatty Liver of Pregnancy (AFLP)


  • Often presents with progressive nausea and vomiting
  • Can lead to hepatic rupture
  • Patients with HELLP syndrome who present with frank hepatic failure should be screened for AFLP
• AFLP


  Unclear whether it is truly in the spectrum of pre-eclamptic syndromes or an entirely separate entity with similar signs and symptoms
• More than 50% of patients with AFLP will also have hypertension and proteinuria
• AFLP presents in approximately 1 in 10,000 pregnancies and has a high mortality rate
• A number of AFLP patients will have fetuses with long-chain hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency
• To differentiate AFLP from HELLP

  Laboratory tests associated with liver failure such as elevated ammonia level, blood glucose less than 50 mg/dL, and markedly reduced fibrinogen and antithrombin III levels have been associated with AFLP
• Management of AFLP patients

  Supportive, while liver transplant has been used, some studies have reported that AFLP can be treated in many patients without requiring this aggressive intervention
• Diagnosis of HELLP Syndrome

  • Hemolytic anemia
  • Schistocytes on peripheral blood smear
  • Elevated lactate dehydrogenase
  • Elevated total bilirubin
  • Elevated liver enzymes
  • Increase in aspartate aminotransferase
  • Increase in alanine aminotransferase
  • Low platelets
  • Thrombocytopenia
• Mild Preeclampsia


  • Induction of labor is the treatment of choice for pregnancies at term, unstable preterm pregnancies, or pregnancies where there is evidence of fetal lung maturity
  • For stable preterm patients, bed rest and expectant management is the most commonly employed management plan until effecting delivery at 37 weeks' gestation or until delivery is otherwise indicated
  • Betamethasone is given to enhance fetal lung maturity
  • Patients are often, though not always, started on magnesium sulfate therapy for seizure prophylaxis during labor and delivery, and should be continued for 12 to 24 hours after delivery
• Severe Preeclampsia


  • Patients should be stabilized using magnesium sulfate for seizure prophylaxis and hydralazine or labetalol for BP control
  • If the gestational age is between 24 and 32 weeks, expectant management to allow time for treatment with betamethasone and further fetal maturity is often used
  • Beyond 32 weeks of gestation or in a severe preeclamptic patient with signs of renal failure, pulmonary edema, hepatic injury, HELLP syndrome, or DIC, delivery should ensue immediately
  • Seizure prophylaxis is usually continued 24 hours postpartum or until the patient improves markedly
  • Antihypertensive medications (most commonly labetalol and nifedipine) should be used, and patients may need to continue medications for several weeks after release to home
  • Corticosteroid treatment can decrease the amount of time until the nadir and return to normal platelet levels in patients with HELLP syndrome
• Women who develop preeclampsia during their first pregnancy will have a 25% to 33% recurrence rate in subsequent pregnancies
• In patients with both chronic hypertension and preeclampsia, the risk of recurrence is 70%
• Low doses of aspirin prior to and during subsequent pregnancies to decrease the risk of preeclampsia, IUGR, and preterm deliveries have been studied, with mixed outcomes
• Calcium supplementation has also been associated with decreased rates of subsequent preeclampsia, but one large randomized controlled trial found no difference between calcium and placebo
• Eclampsia


  • The occurrence of grand mal seizures in the preeclamptic patient that cannot be attributed to other causes
  • 25% of women with eclampsia were originally found to have only mild preeclampsia before the onset of seizures
  • Eclampsia may also occur without proteinuria
  • Complications include cerebral hemorrhage, aspiration pneumonia, hypoxic encephalopathy, and thromboembolic events
• Eclamptic seizures


  • Tonic-clonic in nature
  • May or may not be preceded by an aura
  • Develop before labor (25%), during labor (50%), or after delivery (25%)
  • Most postpartum seizures occur within the first 48 hours after delivery, but will occasionally occur as late as several weeks after delivery
• Treatment of Eclampsia


  1. Seizure management starting with the ABCs (airway, breathing, circulation)

  2. Hypertension management using hydralazine

  3. Seizure control and prophylaxis with magnesium sulfate

  4. Delivery initiated only after the eclamptic patient has been stabilized and convulsions have been controlled
• Magnesium sulfate therapy in Eclampsia


  • Initiated at the time of diagnosis and continued for 12 to 24 hours after delivery
  • Goal is to reach a therapeutic level while avoiding toxicity through careful clinical monitoring