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Preeclampsia

What is preeclampsia?

Preeclampsia (PE) is a serious condition characterized by high blood pressure and protein in the urine (proteinuria), developing anytime from the late second or third trimester [1] to shortly after delivery [2]. It is one of the most serious conditions associated with pregnancy as it can quickly turn life-threatening for both the mother and baby unless treated as early as possible. Preeclampsia was previously known as toxemia of pregnancy as it was believed to result from a toxin present in the bloodstream of a pregnant woman. However, this theory has lately been discarded [3].

Are there different types of preeclampsia?

It can be classified into the following, depending on the etiology and symptoms:

  • Preeclampsia-eclampsia [4]: The common type of PE often advancing from gestational hypertension between the 20th week of gestation and a few hours after delivery
  • Preeclampsia superimposed on chronic hypertension: Preeclampsia further complicating the high BP originally resulting due to another cause, usually chronic hypertension. Women suffering from conditions like diabetes mellitus, chronic kidney disorders and lupus erythematous are also at an increased risk of superimposed preeclampsia [5]
  • Atypical preeclampsia [6]: Have all the usual symptoms of the condition without the characteristic high blood pressure or protein in the urine

What causes preeclampsia?

Although the exact causes are still unknown, some placental abnormalities have been found to be responsible in causing the complication. Researchers are still trying to find the triggering factors for the problems with the placenta [2].

Preeclampsia Risk Factors

  • Genetic factors (family history of preeclampsia or high blood pressure in pregnancy)
  • Being overweight or obese [7]
  • First pregnancy or having been pregnant before but now being pregnant for the first time with a different partner [8]
  • Carrying twins or triplets [2]
  • Being over 40 years of age
  • History of kidney diseases, diabetes [9], rheumatoid arthritis or lupus
  • Antiphospholipid antibody syndrome
  • Poor diet and nutrition
  • Immune system problems in the mother [3]

Preeclampsia Pathophysiology

Once the egg implants itself to the uterine wall, it produces multiple root-like growths (villi) that keep it attached to the lining. The blood vessels within the uterus supplies nutrients to the villi so they can grow and develop into the placenta. These blood vessels also change shape in the first trimester to help the placenta grow properly. Sometimes, the blood vessels fail to transform properly, interrupting the nutrient supply to the developing placenta. The abnormal placental growth may eventually lead to PE [10]. At the same time, abnormal kidney functioning causes essential proteins to leak into the mother’s urine from the bloodstream, causing the symptoms of proteinuria. The exact factors preventing the proper transformation of the blood vessels in the uterus are not known. Inherited genetic changes may be responsible to some extent as the condition usually runs in families [10]. Some antigen acquired from the father may trigger an abnormal immune reaction in the mother’s body, causing the blood vessels to narrow, leading to high blood pressure [11].

How to prevent preeclampsia?

Complete prevention is not possible due to the unknown etiology. The only way to prevent the condition from turning serious is early detection followed by prompt management [3]. Due to this reason, it is essential to go for regular prenatal checkups and follow your doctor’s instructions regarding a healthy pregnancy. Women with chronic high blood pressure should take proper measures to lower the BP before getting pregnant. Although, precautions taken to avoid high blood pressure in pregnancy do not always minimize the chances of developing preeclampsia, taking the following measure may help reduce the risk:

  • Following a low-sodium diet for keeping your BP low
  • Including ample amounts of healthy protein in your diet
  • Staying well-hydrated [12]
  • Avoiding fatty and junk foods
  • Doing regular pre-natal yoga or light exercise

According to some researches, taking calcium supplements and a low-dose aspirin may help in prevention, especially in high risk women [13]. Consulting an expert is recommended before considering such preventive measures.

What are the signs and symptoms of preeclampsia?

  • High blood pressure (140/90 mmHg or higher) [14]
  • High levels of protein in the urine [3]

Both the above symptoms are considered the earliest warning signs of PE. But, as it is not possible for you to detect these symptoms at home, you should look out for:

  • Changes in vision (temporary vision loss, blurred vision, light sensitivity and black spots or floaters) [15]
  • Severe headaches that refuse to go away [13]
  • Nausea and vomiting
  • Fatigue and dizziness
  • Sudden weight gain (3-5 pounds within a week)
  • Upper abdominal pain, usually on your right side, just under the ribs
  • Lower back pain [27]
  • Abnormal swelling (edema) of face, hands and feet [16]
  • Reduced urine output
  • Dark or reddish urine color

Although symptoms like swollen hands and foot and weight gain are normal in pregnancy, make sure to call your doctor in case of sudden changes in weight or edema.

What are the possible complications of preeclampsia?

PE hinders the blood flow to the placenta, increasing the chances of various complications by disrupting the oxygen and nutrient supply to the fetus [12].

Effects on the Baby

  • Lower than average birth size and weight
  • Epilepsy
  • Cerebral palsy [7]
  • Vision and hearing problems
  • Breathing difficulties after birth due to incomplete lung maturation [17]
  • Intrauterine growth restriction [4]
  • Learning disabilities as growing up
  • Death within the womb (stillbirth)

Risks to Mother

  • Premature labor and delivery
  • Placental abruption [15]
  • Lung problems
  • Liver and kidney damage and failure
  • Blood clotting disorders [18]
  • Severe bleeding after delivery
  • Water retention in the lungs (pulmonary edema) [7]
  • Stroke
  • Future cardiovascular disorders and heart failure
  • Temporary blindness [7]
  • Eclampsia (seizures)
  • HELLP syndrome (hemolysis, elevated liver enzymes and low platelet count) [3]
  • Death

Postpartum Preeclampsia

As the name suggests, preeclampsia developing after childbirth is referred to as postpartum preeclampsia. It commonly develops within 48 hours of delivery, but can occur any time up to 4-6 weeks after the baby is born (late postpartum preeclampsia). Like the prenatal form, it requires prompt medical attention (bed rest, medication) to prevent seizures and other complications [19].

Preeclampsia Vs Eclampsia

If left untreated, PE advances to eclampsia, a potentially life threatening pregnancy complication characterized by severe seizures. Statistics show about 1 in every 200 cases of PE to advance to eclampsia without proper treatment [20].

Preeclampsia Diagnosis

Diagnostic criteria for the condition include blood pressure over 140/90 mmHg (in two readings taken 6 hours apart) [3] along with protein in the urine. These symptoms are detected in the routine blood and urine tests during your prenatal checkup [21]. Positive results in either or both the above tests call for additional diagnostic procedures including:

  • Physical examination to detect abnormal swelling or edema, signs of fluid retention and sudden weight gain [1]
  • Eye exams
  • Blood tests to detect blood clotting disorders (platelet count) as well as assessing kidney and liver functioning [3]
  • Multiple urine tests within 24 hours to determine how much protein is lost [22]

Your doctor may also order tests and exams for assessing the fetal health (organ development and functioning).

Preeclampsia Differential Diagnosis

  • Chronic hypertension without preeclampsia
  • Primary seizure disorders
  • Chronic renal disease
  • Thrombotic thrombocytopenic purpura [9]
  • Gallbladder and pancreatic disorders
  • Hemolytic-uremic syndrome [23]
  • Antiphospholipid syndrome
  • Acute fatty liver of pregnancy

Preeclampsia Treatment and Management

Delivering the baby is the only way to cure preeclampsia as the high BP associated with it gradually becomes normal following childbirth. However, induction of labor and delivery are not possible unless the woman is nearing full-term (37 weeks pregnant).

Treatment of Mild Preeclampsia

Women with mild preeclampsia before full-term are put on bed rest and are monitored closely at the hospital for any signs of deterioration. Women with no immediate risk of complications may be allowed to go home after the tests while those more at risk of serious problems may have to stay at the hospital for further testing [24].

Monitoring the Mother

  • Blood tests (to check for organ failure and determine the uric acid levels)
  • Blood pressure measurement at least 4 times a day
  • Monitoring fluid intake
  • Urine test for detecting certain proteins (e.g. aspartate aminotransferase or AST and alanine aminotransferase or ALT [25]) in the urine that might indicate liver damage

Fetal Monitoring

  • Fetal ultrasound for assessing fetal growth, checking blood flow to the placenta as well as observing the fetal breathing and movements [25]
  • Doppler ultrasound for checking the functioning of the placenta [21]
  • Non-stress tests (cardiotocography), to electronically monitors the baby’s heart rate and detect any respiratory distress
  • Biophysical profile, a combination of a non-stress test and ultrasound [15]

Medications

  • Antihypertensive drugs to prevent further elevation of BP
  • Magnesium injection and other medications for preventing eclampsia
  • Steroid injections for accelerating the fetal lung development to prepare the baby for delivery [7]

Treatment of Severe Preeclampsia

Doctors recommend induction of labor for women who develop the condition at or after full-term. The readiness and dilation of the cervix is considered to determine the time of inducing labor and ascertain a healthy natural delivery. In severe cases, the baby has to be delivered even before full-term [7] to lower the maternal BP. A c-section (cesarean section) may be performed if it is too early for induction of labor. Intravenous administration of magnesium sulfate during delivery can increase the blood flow to the uterus and prevent seizures [3]. Treatment after delivery involves bed rest, close monitoring and BP medication (if necessary).

Incidence, Prevalence and Mortality Rate of Preeclampsia

It occurs in about 5% of all pregnant women with severe preeclampsia developing in around 1-2% of cases [2] while its postpartum form is quite rare. Studies show the condition to be most prevalent in northern Finland [26]. Approximately 1000 infants born to mothers with PE die each year, mainly due to complications resulting from early delivery [17].

Preeclampsia Recurrence Risk

Women with a history of PE in a previous pregnancy are more likely to develop it in their second pregnancy. The earlier the PE occurred in the previous pregnancy, the higher the chances of developing it again [15].

Preeclampsia ICD-9 and ICD-10 Codes

ICD-9 codes 642.4-642.7 [28] are used for indicating PE while its ICD-10 codes are O11, O14 [29]

Published on February 4th 2014 by under Health Conditions.
Article was last reviewed on 4th February 2014.

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