Preeclampsia is a serious pregnancy complication that affects about 5% of all pregnant women worldwide. It is characterized by high blood pressure and damage to internal organs, most commonly the liver and kidneys.

Although the exact cause of preeclampsia is unknown, several factors have been identified in the blood that may predispose women to develop the condition.

1. Endothelial dysfunction

The endothelium is a thin layer of cells that lines the inside of blood vessels. Its main function is to regulate the passage of fluids and nutrients between the blood and tissues.

In preeclampsia, the endothelium becomes dysfunctional, leading to decreased blood flow to vital organs and increased fluid leakage into surrounding tissues. This dysfunction is thought to be caused by various factors, including inflammation, oxidative stress, and abnormal lipid metabolism.

2. Inflammatory markers

Inflammation is a normal response of the body to injury or infection. However, in some cases, it can become chronic and harmful. In preeclampsia, there is evidence of increased inflammation in the maternal blood and placenta.

This inflammation is thought to be caused by the release of certain cytokines, which are inflammatory proteins that regulate the immune response. High levels of cytokines, such as interleukin-6 and tumor necrosis factor-alpha, are associated with an increased risk of preeclampsia.

3. Anti-angiogenic factors

Angiogenesis is the formation of new blood vessels from pre-existing ones. During pregnancy, angiogenesis is necessary to provide adequate blood supply to the developing fetus.

In preeclampsia, there is a reduction in angiogenic factors, such as vascular endothelial growth factor (VEGF) and placental growth factor (PlGF). This reduction is thought to be caused by the presence of anti-angiogenic factors, such as soluble fms-like tyrosine kinase-1 (sFLT-1) and soluble endoglin (sEng), in the maternal blood.

These factors bind to and sequester VEGF and PlGF, preventing them from promoting angiogenesis.

4. Abnormal lipid metabolism

Lipids are molecules that are essential for various physiological processes, such as energy production and cell membrane synthesis. During pregnancy, there is an increased demand for lipids to support fetal growth and development.

In preeclampsia, there is evidence of abnormal lipid metabolism, characterized by an increase in triglycerides and a decrease in high-density lipoprotein (HDL) cholesterol. This alteration in lipid metabolism is thought to be caused by insulin resistance and inflammation.

5. Oxidative stress

Oxidative stress is a state of imbalance between the production of reactive oxygen species (ROS) and the ability of the body to neutralize them with antioxidants.

ROS are highly reactive molecules that can damage cellular components, such as DNA, proteins, and lipids. In preeclampsia, there is evidence of increased oxidative stress, characterized by an increase in markers of oxidative damage, such as lipid peroxides and protein carbonyls.

This oxidative stress is thought to be caused by various factors, including inflammation and abnormal lipid metabolism.

6. Genetic factors

Although the exact genetic factors that predispose women to preeclampsia are not well understood, there is evidence of a hereditary component to the condition.

Studies have identified various genes that may be involved in the development of preeclampsia, including those that regulate blood pressure, inflammation, and immune function. However, the contribution of these genes to the overall risk of preeclampsia is unclear, and further research is needed to fully understand their role.

7. Vitamin D deficiency

Vitamin D is a fat-soluble vitamin that is important for calcium metabolism and bone health. However, it also has various non-skeletal effects, including the regulation of immune function and blood pressure.

In recent years, there has been growing evidence of an association between vitamin D deficiency and an increased risk of preeclampsia. Studies have shown that maternal vitamin D deficiency is associated with an increased risk of preeclampsia, and that vitamin D supplementation may reduce this risk.

8. Age and obesity

Advanced maternal age and obesity are two well-established risk factors for preeclampsia. Women over the age of 35 and those with a body mass index (BMI) of 30 or higher are at an increased risk of developing the condition.

The exact mechanisms underlying these associations are unclear, but it is thought that they may be related to changes in hormone levels, inflammation, and endothelial dysfunction.

9. Pre-existing medical conditions

Women with pre-existing medical conditions, such as hypertension, diabetes, and kidney disease, are at an increased risk of developing preeclampsia.

The exact mechanisms are unclear, but it is thought that these conditions may contribute to endothelial dysfunction and inflammation. It is important for women with these conditions to receive close monitoring during pregnancy to detect preeclampsia early.

10. Multiple pregnancy

Women carrying multiple fetuses, such as twins or triplets, are at an increased risk of developing preeclampsia.

The exact mechanisms are unclear, but it is thought that the increased demand on the maternal circulation may contribute to endothelial dysfunction and inflammation. It is important for women carrying multiple fetuses to receive close monitoring during pregnancy to detect preeclampsia early.