What causes Preeclampsia?

By Pregnancy & Parenting Team Apr 21, 2017

Affecting 5 to 10 percent of pregnant women, high blood pressure in pregnancy is a common medical problem. Preeclampsia is when a patient has an elevated blood pressure of greater than 140/90, along with too much protein in the urine. Because it can result in complications for both the mother and baby, it is important to know if you develop preeclampsia during the pregnancy.

Diagnosis, effects of preeclampsia

Hypertension is the main part of the diagnosis of preeclampsia. Preeclampsia can affect the patient’s body in a variety of ways, start at different gestational ages and range in severity.
Some patients experience:

  • Swelling in the legs, arms, face or genitals
  • Fluid in the abdomen or lungs

As preeclampsia can affect any organ in the body, it can also cause:

  • Headache
  • Blurred vision
  • Liver failure
  • Kidney failure
  • Platelets, abnormalities in the blood.

Those at elevated risk for preeclampsia

The most important risk factor is having your first baby. Two-thirds of all preeclampsia cases occur in women having their first baby.
However, there are many other conditions that put patients at increased risk including:

  • Those over age 40
  • IVF
  • Family history of preeclampsia
  • Obesity
  • Twins
  • Preeclampsia in a previous pregnancy
  • Chronic hypertension
  • Kidney disease
  • Lupus
  • Diabetes

The risk also increases in those women who have limited sperm exposure with the same partner before conception.

A previous normal pregnancy with the same partner is associated with a lower preeclampsia risk. However, the decreased risk is lost with a change of partner or with a prolonged interval between pregnancies.

The role of the father

Studies have shown that the history of the father is an important risk factor for preeclampsia. Men who fathered one preeclamptic pregnancy are nearly twice as likely to father a preeclamptic pregnancy with a different woman — regardless of whether the new partner had a history of preeclampsia.

Causes of preeclampsia

Though the precise cause of preeclampsia is unknown, theories suggested include:

  • Abnormal placenta implantation into the uterus early in the pregnancy
  • Abnormal blood vessel development
  • Blood clotting defects
  • Blood vessel damage
  • The mother’s immune system
  • Genetics
  • Overactive inflammation response

Preeclampsia prevention

There has not been much success in finding ways to prevent preeclampsia despite many studies. Trials have evaluated protein or salt restriction, zinc, magnesium, fish oil, vitamin C or E, calcium, water pills, blood pressure medication and blood thinners without revealing a proven benefit in preventing or lowering the risk of preeclampsia.

One method of prevention has been shown to work. Recently, large studies have proven that low dose aspirin (81 mg) can help prevent preeclampsia in patients at risk. Patients with a history of preeclampsia, chronic hypertension, kidney disease, diabetes or multiple gestations can decrease their risk of preeclampsia by taking aspirin in low doses throughout pregnancy, starting at 12 to 28 weeks gestation.