Pre-eclampsia

New research at Mount Sinai Hospital leading to earlier diagnoses and improved treatments for pre-eclampsia

Incidence
Approximately three to seven per cent of pregnant women develop pre-eclampsia.

Signs and symptoms
The most prominent symptom of this disorder is hypertension, which is characterized by a blood pressure greater than 140/90. Another symptom is proteinuria, which is an excess of protein in the urine. Other common problems associated with pre-eclampsia include severe headaches, temporary loss or blurring of vision, light sensitivity, dizziness, decreased urination, sudden weight gain, abdominal pain on the upper-right side, nausea or vomiting, and sudden weight gain of more than two pounds per week.

Risk factors
The risk of pre-eclampsia is higher in first-time pregnancies, for pregnant women between the ages of 20 and 40, and in those with a prolonged interval between pregnancies. Pre-eclampsia normally occurs after the 20th week of pregnancy.

Complications
Women with pre-eclampsia may also develop a condition called ‘eclampsia,’ which includes the development of seizures. If left untreated, eclampsia can lead to severe organ damage for the mother and baby.

As well, a serious complication called placental abruption may occur, which is the separation of the placenta from the wall of the uterus before delivery (resulting in heavy bleeding and placental damage).

Underlying causes
Pre-eclampsia refers to a set of symptoms rather than any single causative factor, and researchers believe there may be different causes for the condition.

However, it is known that in a woman with pre-eclampsia, tiny blood vessels surrounding the baby’s placenta (called placental villi) release natural inhibitory factors important for its growth but which interfere with the mother’s own blood vessels and increase her blood supply. This triggers some of the cascade of events characterizing pre-eclampsia.

Related disorders
Pre-eclampsia is one of the four disorders characterized by high blood pressure during pregnancy. The other three related disorders are: gestational hypertension, which does not involve proteinuria but can sometimes lead to pre-eclampsia; chronic hypertension, which occurs before 20 weeks of pregnancy or can last until 12 weeks after pregnancy; and pre-eclampsia superimposed with chronic hypertension in women whose chronic hypertension before pregnancy worsens.

Treatment
Although the only cure for pre-eclampsia is delivery, there are methods to treat many of the symptoms.

Antihypertensives are used to lower blood pressure until delivery. For severe cases, corticosteroids can improve liver and platelet functioning and prolong pregnancy, and anticonvulsive medications can reduce the risk of seizure. Bed rest is also recommended to increase blood flow to the placenta and lower blood pressure. If pre-eclampsia arises towards the end of the pregnancy, an early delivery may be the best option.
 

 Meet the Experts:

Dr. John Kingdom, Maternal Fetal-Medicine Specialist in the Department of Obstetrics and Gynaecology and a scientist at the hospital’s Samuel Lunenfeld Research Institute, recently discovered a new mechanism for the blood thinning drug, Heparin, in the prevention of pre-eclampsia. Heparin is used as a drug for pre-eclampsia due to its ability to restart a limited degree of new blood vessel growth (angiogenesis) in some pre-eclamptic pregnancies, thus reducing the risk of high blood pressure.

Lunenfeld scientist Dr. Isabella Caniggia is a leading authority on placental development and pre-eclampsia. Dr. Caniggia hopes that in the future, a simple blood test will predict whether a pregnant woman is at risk for pre-eclampsia. A few years ago, she licensed her biomarker findings to help develop a diagnostic tool that will detect and manage pre-eclampsia in expectant mothers over the next five years. Potentially, physicians will use a point-of-care kit to detect and measure increased levels of the biomarker endoglin in expectant mothers who are at increased risk of pre-eclampsia.