Preeclampsia is a disorder that only affects pregnant women after twenty weeks of pregnancy. It causes hypertension and the appearance of proteins in urine. The underlying mechanism is related to the blood vessel wall dysfunction (vascular endothelium) and vasospasm, which damages the kidneys and, in severe cases, can harm other organs, such as the brain and the liver. Rarely, it develops six weeks after delivery.
The exact cause is unclear, but a key feature is the development of an abnormal placenta. Normally during pregnancy, the spiral arteries of the uterus dilate ten times their normal size and become large uteroplacental arteries that can deliver large quantities of blood to the developing fetus. In preeclampsia, these arteries become fibrous, causing them to narrow, which means less blood gets to the placenta. A poor bloody supply to the placenta leads to intrauterine growth restriction and even deaths of the fetus. In severe cases, this poorly supplied placenta releases pro-inflammatory proteins that enter into the mother’s circulation and cause endothelium, that line blood vessels, to become dysfunctional, which in turn causes vasoconstriction or narrowing of the blood vessel and majorly affects the kidneys in a way that makes them retain more salt. Vasoconstriction and salt retention result in hypertension.
There can be local areas of vasospasm which means less blood might reach certain parts of the body.
For example, reduced blood flow to the kidneys that are particularly susceptible can cause glomerular damage, leading to oliguria, which means an abnormally low amount of urine production, and proteinuria, which means protein in the urine. Usually, the kidneys do a pretty good job of preventing proteinuria, so proteinuria will indicate glomerular damage and is classically seen in preeclampsia. Reduced blood flow to the eye’s retina will cause blurred vision, a sensation of seeing flashing lights, and decreased vision. Reduced blood flow to the liver can cause severe liver damage. 10-20% of women with severe eclampsia have cardiovascular disease.
Increased vascular permeability causes generalized edema. Pulmonary edema and cerebral edema are also seen.
Based on severity, pre-eclampsia is divided into the following types;
Preeclampsia impacts 5-8% of all births in the U.S.
There can be a wide range of symptoms; for some women, there might be no symptoms whatsoever or only mild ones, whereas, for others, it can be life-threatening. The occurrence of seizures on the background of pre-eclampsia is called eclampsia. Epigastric pain is a severe cardinal symptom of preeclampsia
Health care providers closely monitor pregnant patients' blood pressure, and urine as the first sign of developing preeclampsia is hypertension. When diagnosing preeclampsia, hypertension is defined as systolic blood pressure >140mm Hg and diastolic blood pressure >90mmHg.In severe preeclampsia, the systolic blood pressure is>160 mm Hg, and diastolic pressure can be >110mmHg. These extreme blood pressures can lead to hemorrhagic stroke or placental abruption, i.e., when the placenta detaches prematurely from the uterine wall.
Following tests aid in making the diagnosis;
Some disorders that can mimic pre-eclampsia are;
Because all the problems of eclampsia and preeclampsia stem from placental dysfunction, the ultimate treatment is delivery of the fetus and placenta. The patent diagnosed with pre-eclampsia is admitted to the hospital to monitor her health and blood pressure closely. The decision to induce delivery depends on how far along the pregnancy is, the severity of the disease, and how it affects the health of the mother and fetus. If the onset of symptoms happens after delivery, the goal is to manage the symptoms that slowly subside after delivery. Additional measures prevent end-organ damage by supplemental oxygen and medication to control seizures and other complications like stroke and placental abruption.
Most women deliver healthy babies and recover completely. However, preeclampsia, in others, can be life-threatening for both mother and the baby. The baby of a pre-eclamptic mother may be of low birth weight, may be born preterm, or may have improper lung development. Some women experience complications. The risk of developing pre-eclampsia and its complications in successive pregnancies also increases.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by Dr.Saad Zia on April 28th, 2023.