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What is Preeclampsia?

Preeclampsia is a disease of pregnancy that affects the lining of the mother's blood vessels causing high blood pressure, leaking of fluid from the blood vessels, and damage to multiple organs. Preeclampsia is believed to be caused by an abnormal placenta releasing higher than normal amounts of substances that control the growth of blood vessels and the placenta [1-4]

Preeclampsia tends to be milder when it occurs late in pregnancy, but can progress very quickly at anytime to a severe form with the development of very high blood pressure and seizures (eclampsia). Severe preeclampsia can also cause fetal growth restriction, placental abruption (detachment of the placenta), stroke, pulmonary edema (fluid in the lungs) , bleeding disorders, kidney failure, and liver swelling.

Who gets Preeclampsia?

About 5% to 7% of all pregnancies are affected by preeclampsia Women are more likely to develop preeclampsia during their first pregnancy, if they are over the age of 40,  have diabetes, a multiple gestation (twins), a family history of preeclampsia, had preeclampsia in a previous pregnancy, or  they have had  in vitro fertilization.  Women with antiphospholipid syndrome, chronic hypertension, and chronic renal disease are ten times more likely to develop preeclampsia than women without these conditions [5-7}.

Signs and Symptoms of Preeclampsia

Most women with early preeclampsia do not have symptoms. When symptoms occur they usually occur in the second half of pregnancy and may include

  • Persistent headache not relieved by mild pain killers
  • Visual disturbance such as double vision, sensitivity to light, blurred vision, dimmed vision., loss of vision, or flashing lights (fireworks)
  • Pain in right upper or middle upper abdomen
  • Nausea or vomiting
  • Difficulty breathing, new onset shortness of breath, cough, or rapid breathing
  • Dark colored urine, blood in urine, or decreased amount of urine
  • Decreased fetal movement
  • Sudden weight gain

Women should be advised to seek immediate medical advice  if they experience any of the above symptoms

How is Preeclampsia Diagnosed?[9,10]

The American College of Obstetricians and Gynecologists (ACOG) recommends that preeclampsia should be  diagnosed if the following conditions are met:

High blood pressure occurring for the first time after 20 weeks

  • A systolic blood pressure (SBP) greater than or equal to 140 mm Hg OR
    a diastolic blood pressure (DBP) greater than or equal to 90 mm Hg on at least two occasions at least 4 hours apart
  • A systolic blood pressure (SBP) greater than or equal to 160 mm Hg OR
    a diastolic blood pressure (DBP) greater than or equal to 110 mm Hg measured on more than one occasion several minutes apart


  • Protein is in the urine (proteinuria). 300 mg or more in a 24 hour urine timed collection  or  a protein/creatinie ratio of at least 0.3 (each measured as mg/dL)
    1+ on dipstick may be used only if the above methods are unavailable



  • Cerebral or visual disturbances (as above noted under symptoms)
  • Pulmonary edema (fluid in the lungs)
  • Low platelet count (less than 100,000 /microliter)
  • Elevated liver enzymes ( transaminases ) to  twice the normal concentration,  severe persistent pain in the right upper or middle upper abdomen that does not respond to medication and is not explained by another condition or both.

    Normal Ranges for Transaminases In Pregnancy

    Alanine aminotransferase , ALT, SGPT 2 - 33 U/L
    Aspartate aminotransferase ,AST, SGOT 3- 33   U/L
  • Renal insufficiency (serum creatinine greater than1.1 mg/dL) ,or a doubling of serum creatinine in the absence of other renal  disease

Women who develop high blood pressure for the first time after 20 weeks, but do not have protein in their urine or severe features of preeclampsia are diagnosed with gestational hypertension (GHTN).

A woman who has chronic hypertension (high blood pressure before 20 weeks) is likely to also have  preeclampsia (superimposed)  if :

  • She develops  protein in her urine for the first time after 20 weeks,
  • The amount of protein in her urine increases dramatically  if she had protein in her urine before 20 weeks
  • Her blood pressure suddenly increases and becomes difficult to control
  • She develops any of the severe features of preeclampsia.

How is Preeclampsia Treated?[9,10]

  • Blood pressure medications are given to reduce the chance of strokes, heart failure, and kidney injury in women with severe hypertension  (SBP greater than or equal to 160 mm Hg or DBP  greater than or equal to 110 mm Hg )
  • Magnesium sulfate is given to treat eclampsia (new onset grand mal  seizures), or  to prevent eclampsia  during labor ,during cesarean section, and after delivery in women with SBP greater than or equal to 160 mm Hg ,  DBP  greater than or equal to 110 mm Hg , OR  with severe features of preeclampsia, HELLP syndrome, or hyperactive reflexes (clonus).
    • Magnesium sulphate more than halves the risk of eclampsia, and reduces the risk of placental abruption [12]
  • Medication (corticosteroid) to help the fetal lungs mature and reduce other complications of being born prematurely are  given to women  with a viable fetus who must be delivered before 34 weeks' .
  • Delivery is the only cure for preeclampsia. However, the timing of delivery will depend on the severity of the disease and gestational age. The mode of delivery (vaginal or cesarean) is determined by the age of the fetus, presentation, cervical status, and maternal or  fetal conditions.

ACOG recommends [8-10]

  • Preeclampsia with severe features or HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome before viability or  at 34 weeks gestational age or after should be delivered when the mother's condition is stable.
  • Gestational hypertension or preeclampsia without severe features at  37 weeks gestational age or after should be delivered
  • Preeclampsia with severe features after viability and before 34 weeks should be hospitalized at a facility with maternal and neonatal intensive care resources.
    • Women with uncontrolled high blood pressure, eclampsia, pulmonary edema, placental abruption, disseminated intravascular coagulation (DIC) , nonreassuring fetal status , or fetal demise should be delivered  after their condition has become stable.
  • Gestational hypertension (GHTN) or preeclampsia without severe features before 37 weeks should have
    • Monitoring for symptoms,
    • Instruction on daily kick counts,
    • Twice weekly blood pressure measurement,
    • Assessment of platelet count, liver enzymes (AST, ALT) , and serum creatinine at least every week .
    • Fetal growth should be checked every three weeks
      • Umbilical artery doppler velocimetry if growth restriction is suspected.
    • Amniotic fluid level should be checked at least once per week,
    • Patients with GHTN should also have their blood pressure taken,  urine checked for protein,  and nonstress tests (NSTs) once weekly.
    • Patients with preeclampsia without severe features should have NSTs twice weekly.
    • Strict bedrest or a low sodium diet are not recommended.
    • Patients should be hospitalized if they develop severe hypertension, severe features of preeclampsia, or fetal growth restriction.

Postpartum (after delivery) ACOG Recommends

  • Blood pressure should be monitored for at least 72 hours after delivery and at 7 to 10 days after delivery or sooner in women with symptoms. Signs and symptoms of preeclampsia should be reviewed with mother  before discharge to home.
  • Medication to control blood pressure  is suggested in women  with persistent SBP 150 mm Hg or higher or DBP of 100 mm Hg or higher on two occasions 4 to 6 hours  apart.
  • Avoid the use of nonsteroidal antiinflammatory agents (e.g. ibuprofen) in women with hypertension that persists for more than one day after delivery.
  • Advise women who have had preeclampsia that they have an increased lifetime risk of cardiovascular disease later in life
  • Women with a history of recurrent preeclampsia or delivery before 37 weeks for preeclampsia  should consider yearly assessment of  their lipids, fasting blood glucose and body mass index (BMI )
  • Preeclampsia and eclampsia can develop up to 4 to 6  weeks postpartum
    • If a woman presents postpartum with new onset high blood pressure  with  headache, or other symptoms such as changes in her vision she should receive parenteral magnesium .


What are the chances that preeclampsia  will occur again in a future pregnancy?

  • Women who had GHTN with their current pregnancy have a 16 to 47 % chance of having  GHTN  and a 2 to 7% chance of having preeclampsia in future pregnancies

  • Overall, women who had preeclampsia with their current pregnancy have a 13 to 53 % chance of having  GHTN   and  a 16 % chance of having preeclampsia in future pregnancies

    • Women who required delivery before  34 weeks for severe preeclampsia,  HELLP syndrome, or eclampsia have a 25% percent chance of recurrence in future pregnancies. The risk of recurrence is as high as 55 % if they required delivery before  28 weeks  [11]

Low dose  "baby aspirin"

ACOG recommends aspirin 80 mg daily in women with chronic hypertension and history of  early onset preeclampsia at less than 34 weeks or preeclampsia in more than one prior pregnancy.

The National Institute for Health and Clinical Excellence (NICE) recommends women at high risk of pre-eclampsia should take 75 mg of aspirin daily from 12 weeks until the birth of the baby [13,14] .

Women at high risk include: hypertensive disease during a previous pregnancy ,chronic kidney disease ,autoimmune disease such as systemic lupus erythematosis or antiphospholipid syndrome , type 1 or type 2 diabetes and chronic hypertension .  In addition NICE recommends women with more than one moderate risk factor for pre-eclampsia should to take 75 mg of aspirin daily from 12 weeks until the birth of the baby. Moderate risk factors are: first pregnancy , age 40 years or older, pregnancy interval of more than 10 years , body mass index (BMI) of 35 kg/m2 or more at first visit , family history of pre-eclampsia multiple pregnancy.

Reviewed by Mark Curran, M.D. FACOG


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