During pregnancy, women are at greater risk of developing high blood pressure. There are multiple types of high blood pressure conditions that occur during pregnancy, but preeclampsia may be one of the most dangerous for both the mother and the fetus. Preeclampsia causes high blood pressure, reduces delivery of oxygen and nutrients to the developing baby, often causes large amounts of protein in the mother’s urine, and can also increase the risk of seizures.
The exact causes of preeclampsia are not fully understood, but most experts believe that the emergence of preeclampsia is related to the development of the placenta and the blood vessels in the uterine walls. After the fertilized egg attaches to the wall of the uterus, the placenta begins to develop. As it develops, blood vessels grow from the uterine walls. These blood vessels help the placenta fully attach to uterus and run through the placenta allowing it to provide nutrients and oxygen to the developing fetus.
As these blood vessels grow through the placenta, they gradually become wider in order to provide increased blood flow and nutrients to the fetus. It is believed that preeclampsia and the high blood pressure that results is caused when the blood vessels do not grow and develop correctly or if they fail to widen enough to accommodate the increased blood flow. The increased blood flow and constricted blood vessels raise the blood pressure of the mother, and if the mother already suffers from chronic hypertension, there could be a risk of death for her and the baby.
Though doctors believe they understand the basic mechanism by which preeclampsia develops and its relationship to blood vessels and the placenta, it is still unknown why the blood vessels and placenta develop incorrectly in the first place. Currently, there are many theoretical preeclampsia causes that are still being researched and studied.
Insufficient Blood Flow to the Uterus
One of the most accepted theories for preeclampsia causes is insufficient blood flow to the uterus. It is believed that if the blood flow is insufficient when the placenta is first developing, the blood vessels will not grow and widen sufficiently. When the blood flow increases later in the pregnancy, the constricted vessels and stunted development cause high blood pressure.
There are a number of different conditions that can cause insufficient blood flow to the uterus such as chronic high blood pressure, diabetes, obesity, kidney failure, and poor nutrition. Research has suggested each of these conditions and disorders are linked to development of preeclampsia.
Genetic Preeclampsia Causes
Scientists have not identified any specific genes that increase the risk of preeclampsia, but evidence suggests that preeclampsia may have genetic causes. If a woman’s mother or sisters has had preeclampsia, she has a higher risk of developing preeclampsia herself. Family history of preeclampsia also has a strong statistical relationship to it developing in a first time parent.
Immune System Disorders
There are a large number of experts in the medical community who believe that autoimmune disorders are one of the primary preeclampsia causes. If the immune system malfunctions and causes inflammation in the placenta or in the blood vessels of the uterus, it may delay or prevent healthy growth and development. Doctors have not discovered why a mother’s immune system may respond to the growth of the placenta or how to prevent this autoimmune response.
Other Preeclampsia Causes
There are a few other risk factors that increase the risk of preeclampsia and may be related to the causes of the disorder. For example, pregnant women who are over the age of 40 have a higher risk of preeclampsia than others. Additionally, first time mothers are at higher risk as well as those who are having a multiple pregnancy.