Gestational Hypertension

last authored: Dec 2011, David LaPierre
last reviewed:

 

 

 

Introduction

Gestational hypertension, previously known as pregnancy-induced hypertension, is hypertension of systolic BP >90mmHg, with onset after 20 weeks gesational age. It is one of the most common disorders of pregnancy, affecting 5-6% of all pregnancies (Sibai, Dekker, and Kupferminc, 2005).

 

Pre-eclampsia is the next step in the disease progression, representing end-organ damage. This can include proteinuria, cerebral symptoms, or epigastric or right-upper quadrant pain. It occurs in 1-2% of pregnant women (Sibai, Dekker, and Kupferminc, 2005). Severe pre-eclampsia is defined as onset before 34 weeks gestation, heavy proteinuria, or one or more adverse conditions other than proteinuria.

 

Eclampsia occurs in 1:2000 pregnancies. It is a life-threatening condition that can lead to rapid death of both mother and fetus. It is characterized by seizures and other organ dysfunction such as pulmonary embolism. HELLP syndrome, or Hemolysis, Elevated Liver enzymes, Low Platelets, is a devestating consequence that can accompany eclampsia.

 

Pre-existing hypertension is defined as hypertension <20 weeks gestation. It is present in 1% of pregnant women. Pre-eclampsia can develop secondary to pre-existing hypertension.

 

Given the potential mortality associated with hypertensive disease, screening during pregnancy is essential. Sufficient staff, diagnostics, and treatments should be available to women who are displaying evidence of worsening condition, and transport should be arranged as necessary.

 

 

 

The Case of Esther W.

Esther is a 34 year-old woman pregnant with her third child. She has not seen a health care provider during her pregnancy, and estimates herself to be 28 weeks gestation. She presents to the emergency department with an increasingly severe headache that as lasted 48 hours. The nurse takes her blood pressure, which is 176/98.

return to top

 

 

 

Causes and Risk Factors

There is no single predictor of gestational hypertension or worsening disease, but identified risk factors include:

Patient profile

  • black, Scandanavian, or Southeast Asian
  • age <18 or >40
  • obesity
  • lower SES
  • NON smoker
  • cocaine, amphetamine use
  • mother or sister with preeclampsia (suggests genetic factors)

Past history

  • previous pre-eclampsia
  • thrombophilias
  • elevated triglycerides
  • hypertension
  • renal disease
  • diabetes
  • connective tissue disease
  • peridontitis
  • FHx of early CV disease

 

Current pregnancy

  • first pregnancy
  • last pregnancy >10y or <2 y ago
  • twin pregnancies
  • new partner
  • infection during pregnancy

return to top

 

 

 

Pathophysiology

While the etiology of gestational hypertension is unknown, it appears that improper placental development and abnormal invasion of uterine vessels leads to vascular endothelial dysfunction, with an imbalance of thromboxane (vasoconstrictor) and prostaglandin (vasodilator). This results in increased permeability, hypercoagulability, and diffuse vasospasm. Increased vasospasm leads to increased systemic pressure. There also a belief that women prone to gestational hypertension have an increased sensitivity of their vasculature to the effects of angiotensin II.

 

The increased incidence observed in patients using barrier contraception, in multiparous women conceiving with a new partner, and in nulliparous women, suggests a potential immunologic role.

 

Increased risk with family history suggests the role of genetics in some cases.

return to top

 

 

 

Adverse Conditions Associated with Gestational Hypertension

Neurological

  • headache
  • visual disturbance
  • seizures

Cardiovascular and Pulmonary

  • systolic BP >160 mmHg
  • diastolic BP >110 mmHg
  • chest pain
  • dyspnea
  • pulmonary edema

 

Renal

  • elevated creatinine
  • serium albumin <20g/L

Hepatic

  • epigastric/right upper quadrant pain
  • severe nausea or vomiting
  • elevated liver enzymes

Hematological

  • decreased platelets
  • DIC
  • HELLP syndrome

 

Fetal

  • IUGR
  • oligohydramnios
  • absent or reversed end diastolic umbilical artery flow
  • placental abruption
  • prematurity
  • fetal compromise
  • death

 

return to top

 

 

 

Signs and Symptoms

  • history
  • physical exam

History

As described above, symptoms of preeclampsia include:

  • headache
  • visual disturbances (blurred vision, scotomata)
  • epigastric pain, RUQ, or chest pain
  • dyspnea
  • nausea and vomiting
  • decreased urine output
  • thirst
  • edema
  • tremulousness, irritability
  • somnolence

Eclampsia symptoms include:

  • worsening headache
  • seizures

Physical Exam

Ensure accurate blood pressure is taken. Non-severe hypertension should be confirmed with readings >6 hours apart, while severe hypertension should only be diagnosed with two readings >15 min apart.

Hypertension in a previously normotensive woman is defined as greater than diastolic 90mmHg.

Systolic prssure above 140mmHg, or 30 mmHg above preterm levels, should be carefully noted. However, as sBP can normally vary, it is not diagnostic.

Severe hypertension is defined as sBP >160 mmHg or dBP >110 mmHg.

 

Findings of worsening disease can include:

  • tremulousness, irritability
  • diffuse edema (often seen in normal pregnancy)
  • papilledema
  • diplopia
  • hyperreflexia/clonus
  • increased jugular venous pressure
  • petechiae and bruising can suggest coagulopathy
  • right upper quadrant or mid-epigastric tenderness
  • coma

Fetal evaluation should be done, as available:

  • movements, as noted by mother
  • non-stress test
  • ultrasound for growth and biophysical profile
  • doppler flow studies

return to top

 

 

 

Investigations

  • lab investigations
  • diagnostic imaging

Lab Investigations

Lab investigations should include (with associated abnormal findings in brackets):

  • hemoglobin (often elevated due to hemoconcentration)
  • WBC (increased)
  • platelets (decreased)
  • creatinine, urea, uric acid (increased)
  • blood film for hemolysed cells
  • PTT, INR, fibrinogen, D-dimer (increased)
  • ALT, AST, bilirubin, LDH (increased)
  • fragmented RBCs on smear

urine dipstick

  • 2+ significant
  • 3-4+ severe

24 hour urine collection or a protein/creatinine ratio

  • >300mg/24hr
  • >5g/24hr severe

Diagnostic Imaging

As described, imaging of the fetus may include:

  • non-stress test
  • fetal ultrasound for growth and biophysical profile
  • doppler flow studies

return to top

 

 

 

Screening

Screening is important to identify women who are developing signs and symptoms. Regular prenatal visits should be provided, assessing for symptoms, blood pressure and proteinuria. Further investigations may be carried out as clinical suspicion suggests.

return to top

 

 

 

Differential Diagnosis

Other conditions that can resemble preeclampsia include:

Conditions that can resemble HELLP syndrome include:

return to top

 

 

 

Prevention

While the evidence of measures for prevention are not convincing, the following is recommended:

Low risk: calcium supplementation if diet is poor.

Increased risk: low-dose ASA, started before 16 weeks; calcium supplementation, regardless of dietary intake.

For all patients: avoid weight gain between pregnancies

return to top

 

 

 

Treatments

Hypertensive disease can be life-threatening and should be aggressively managed, with a goal of 130-155 mmHg systolic. If severe hypertension or other findings are present, blood pressure, proteinuria, and fetal well-being should be closely monitored, initially as an inpatient until stable.

 

Mild disease

Mild disease can be followed as an outpatient, with weekly visits (or more frequent). This should include clinical assessment, labs, and non-stress test. Bed rest in the left lateral decubitus position may be helpful but is unproven. Sodium and fluid restriction are not as helpful as in essential hypertension. Low-dose aspirin and calcium should be given.

 

Always get repeat readings and assess the status of the baby before instituting medication treatment. Drugs to consider include methyldopa, labetolol, hydralazine, or nifedipine.

Avoid diuretics and ACE inhibitors due decreased intravascular volume, risk of uterine ischemia and teratogenicity for ACE.

 

 

Severe disease (BP >160/110, preclampsia, or eclampsia)

Women with severe hypertension, preeclampsia, or eclampsia should be hospitalized.

Acute control of blood pressure should be obtained with labetalol or nifedipine. Hydralazine is a third line choice. Methyldopa is not helpful, given its long time of onset. Avoid reducing the blood pressure too quickly, however, to avoid hypoperfusion of the placenta.

 

Magnesium sulfate (MgSO4) should be used for prevention of worsing eclampsia and seizures.

 

Give fluid cautiously, as fluid overload can result in pulmonary edema. Fluid status should be monitored via Foley catheter.

 

Control pain, anxiety, and nausea and vomiting, as these have a significant impact on blood pressure.

 

If seizures begin, call for help. Maintain the mother in the lateral position. Protect the airway and provide oxygen. Treat with magnesium bolus, followed by continuous infusion. Do not give magnesium too quickly, as it can cause toxicity (loss of reflexes, flushing, somnolence, paralysis, respiratory distress, and heart block). Calcium gluconate is the antidote for toxicity. Assess for abruption following a seizure.

 

Delivery is the definitive treatment. If under 34 weeks, treat with glucocorticoids for fetal lung development if possible. If a decision is made to wait, perform daily non-stress tests. Weigh the risks and benefits of induction vs Cesarean section.

 

A drop in platelets, as seen with HELLP syndrome, can result in significant risk for bleeding. Consider transfusion of blood, platelets, or corticosteroids prior to delivery.

 

Postpartum management

Risk of seizures is high in first 24 hours postpartum, requiring continued MgSO4 for 12-24 hours. Seizures can occur up to 30 days postpartum. Blood pressure control should continue as an outpatient as necessary.

Treatment with prophylaxis for thromboembolism should be considered, especially in cases of C/S, obesity, or bedrest.

 

A clear care plan needs to be in place for outpatient follow-up to ensure blood pressure normalizes.

return to top

 

 

 

Consequences and Course

If treated early, the prognosis is usually good. However the following can also occur:

Maternal

  • seizure
  • stroke
  • HELLP syndrome
  • left ventricular failure and pulmonary edema
  • pleural effusion
  • hepatic failure
  • renal failure
  • placental abruption
  • death

Fetus

  • fetal growth restriction (10-25%)
  • preterm delivery (15-67%)
  • oligohydramnios
  • subcapsular or intraventricular hemorrhage
  • increased rate of Cesarean section
  • hypoxia
  • death

return to top

 

 

 

Resources and References

Sibai B, Dekker G, Kupferminc M. 2005. Pre-eclampsia. Lancet. 365(9461):785-99.

British Columbia Reproductive Care Program. 2006. Hypertension in Pregnancy Guideline.

Merck manual of medical information.

return to top

 

 

Topic Development

authors: Reuben Kiggundu, David LaPierre

reviewers:

return to top