Preeclampsia

1 What is Preeclampsia?

 is defined as sustained elevation in BP in pregnancy after 20 weeks of gestation in the absence of pre-existing hypertension.

The diagnostic dyad includes:

  • Sustained BP elevation of ≥ 140/90.
  • Proteinuria on dipstick of 1-2+ or ≥ 300 mg on a 24 hr urine collection.

Severe Preeclampsia

It is defined on the basis of finding of at least mild preeclampsia plus anyone of following:

  • Sustained BP elevation of ≥ 160/110.
  • Proteinuria on dipstick of 3-4+ or ≥ 5g on a 24-hr urine collection.
  • Evidence of maternal jeopardy: This may include symptoms (headache, epigastric pain, visual symptoms), thrombocytopenia (platelet count≤ 100000/ml), elevated liver enzymes, pulmonary edema, oliguria(≤750ml/24h) or cyanosis.
  • Edema may or may not be seen.

2 Symptoms

With mild pre-eclampsia, the symptoms are generally related to excess weight gain and fluid retention. Presence of new onset persistent headache, epigastric pain, or visual disturbances would suggest severe preeclampsia.

HELLP syndrome occurs in 5-10% of patients and is characterized by:

  • Hemolysis
  • Elevated liver enzymes
  • Low platelet count

HELLP Syndrome occurs twice as common in multigravidae. It can be confused with thrombotic thrombocytopenic purpura and hemolytic uremic syndrome. HTN, although frequently seen, is not always present.

Conditions associated with HELLP Syndrome include:

  • DIC,
  • abruption placenta,
  • fetal demise,
  • ascites,
  • and hepatic rupture.

3 Causes

The causes of preeclampsia include:

  • Nulliparity
  • Age older than 40 years
  • Black race
  • Family history
  • Chronic renal disease
  • Chronic hypertension
  • Antiphospholipid syndrome
  • Diabetes mellitus
  • Twin gestation (but unaffected by zygosity)
  • High body mass index
  • Homozygosity for angiotensinogen gene T235
  • Heterozygosity for angiotensinogen gene T235

4 Making a Diagnosis

The following diagnostic tests may be required for preeclampsia:

  • CBC
  • Serum alanine aminotransferase and aspartate aminotransferase
  • Serum creatinine
  • Serum uric acid
  • 24 hr urine collection for protein and creatinine
  • Peripheral blood smear
  • Serum lactate dehydrogenase
  • Indirect bilirubin
  • Head CT scanning is used to detect intracranial hemorrhage in selected patients with any of the following:
      • Sudden severe headaches
      • Focal neurologic deficits
      • Seizures with a prolonged postictal state
      • Atypical presentation for eclampsia

Other diagnostic procedures may include:

  • Ultrasonography: Transabdominal, to assess the status of the fetus and evaluate for growth restriction; umbilical artery Doppler ultrasonography, to assess blood flow.
  • Cardiotocography: The standard fetal nonstress test and the mainstay of fetal monitoring.

5 Treatment

Treatments for preeclammpsia vary depending on its type.

In mild preeclampsia

The only definitive cure is delivery and removal of all fetal and placental tissue. However, delivery may be deferred in mild preeclampsia to minimize neonatal complications of prematurity. Management is based on gestational age.

  • Conservative inpatient: Before 36 weeks gestation as long as fetus and mother are stable, mild pre-eclampsia is managed in the hospital , watching for possible progression to severe eclampsia. No antihypertensives or magnesium sulphate is used.
  • Delivery:At ≥ 36 weeks of gestation, delivery is indicated with dilute IV oxytocin induction of labour and continuos infusion of IV magnesium sulphate to prevent eclamptic seizures

In severe pre-eclampsia

  • Aggressive prompt delivery is indicated for severe preeclampsia at any gestational age with maternal or fetal jeopardy.
    • Administer IV magnesium sulphate to prevent convulsions. Give a 5-g loading dose, then continue maintenance infusion of 2g/h.
    • Lower BP to diastolic values between 90 and 100 mm Hg with IV hydralazine and or labetalol.
    • Attempt vaginal delivery with IV oxytocin infusion if mother and fetus are stable.
  • Conservative inpatient management may rarely be attempted in absence of maternal and fetal jeopardy with gestational age 26-34 weeks if BP can be brought below 160/110 mm Hg. This should take place in an intensive care unit in a tertiary care setting. Continuos IV magnesium sulphate should be administered and maternal betamethasone should be given to enhance fetal lung maturity.

6 Prevention

Researchers continue to study ways to prevent preeclampsia, but so far, no clear strategies have emerged.

In certain cases, however, you may be able to reduce your risk of preeclampsia with:

Calcium supplements

Calcium supplementation of at least 1 gram per day is recommended during pregnancy as it prevents preeclampsia where dietary calcium intake is low, especially for those at high risk. Low selenium status is associated with higher incidence of preeclampsia.

Aspirin

Taking aspirin is associated with a 1% to 5% reduction in preeclampsia and a 1% to 5% reduction in premature births in women at high risk. The World Health Organization recommends low-dose aspirin for the prevention of preeclampsia in women at high risk and recommend it be started before 20 weeks of pregnancy.

Physical activity

There is insufficient evidence to recommend either exercise or strict bedrest as preventative measures of pre-eclampsia.

Smoking cessation

In low-risk pregnancies the association between cigarette smoking and a reduced risk of preeclampsia has been consistent and reproducible across epidemiologic studies. High-risk pregnancies (those with pregestational diabetes, chronic hypertension, history of preeclampsia in a previous pregnancy, or multifetal gestation) showed no significant protective effect. It is recommended that smoking be stopped prior to, during and after pregnancy.

7 Risks and Complications

There are several risks and complications associated with preeclampsia.

Problems affecting the mother:

Fits (eclampsia)

Eclampsia causes involuntary contraction of the muscles that pregnant women can experience, usually from week 20 of the pregnancy or immediately after the birth.

During an eclamptic fit, the mother's arms, legs, neck or jaw will twitch involuntarily in repetitive, jerky movements. She may lose consciousness and may wet herself. The fits usually last less than a minute.

While most women make a full recovery after having eclampsia, there's a small risk of permanent disability or brain damage if the fits are severe.

HELLP syndrome

HELLP syndrome is a rare liver and blood clotting disorder that can affect pregnant women. It's most likely to occur immediately after the baby is delivered, but can appear any time after 20 weeks of pregnancy, and in rare cases before 20 weeks.
The letters in the name HELLP stand for each part of the condition:

  • "H" is for haemolysis – this is where the red blood cells in the blood break down
  • "EL" is for elevated liver enzymes (proteins) – a high number of enzymes in the liver is a sign of liver damage
  • "LP" is for low platelet count – platelets are substances in the blood that help it to clot

HELLP syndrome is potentially as dangerous as eclampsia, and is slightly more common. The only way to treat the condition is to deliver the baby as soon as possible. Once the mother is in hospital and receiving treatment, it's possible for her to make a full recovery.

Stroke

The blood supply to the brain can be disturbed as a result of high blood pressure. This is known as a cerebral hemorrhage, or stroke. If the brain doesn't get enough oxygen and nutrients from the blood, brain cells will start to die, causing brain damage and possibly death.

Organ problems

  • Pulmonary oedema – where fluid builds up in and around the lungs. This stops the lungs from working properly by preventing them from absorbing oxygen.
  • Kidney failure – when the kidneys cannot filter waste products from the blood. This causes toxins and fluids to build up in the body.
  • Liver failure – disruption to the functions of the liver. The liver has many functions, including digesting proteins and fats, producing bile and removing toxins. Any damage that disrupts these functions could be fatal.

Blood clotting disorder

The mother's blood clotting system can break down. This is known medically as "disseminated intravascular coagulation".

This can either result in too much bleeding because there aren't enough proteins in the blood to make it clot, or in blood clots developing throughout the body because the proteins that control blood clotting become abnormally active.
These blood clots can reduce or block blood flow through the blood vessels and possibly damage the organs.

Problems affecting the baby:

Babies of some women with pre-eclampsia may grow more slowly in the womb than normal, because the condition reduces the amount of nutrients and oxygen passed from the mother to her baby. These babies are often smaller than usual, particularly if the pre-eclampsia occurs before 37 weeks.

If pre-eclampsia is severe, a baby may need to be delivered before they're fully developed. This can lead to serious complications, such as breathing difficulties caused by the lungs not being fully developed (neonatal respiratory distress syndrome). In these cases, a baby usually needs to stay in a neonatal intensive care unit so they can be monitored and treated.

Some babies of women with pre-eclampsia can even die in the womb and be stillborn. Most of these babies die because of complications related to early delivery.

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