Why the test to predict preeclampsia is hailed as a great news?

Teachable moment in classrooms:

1. blood vessel chapter – layers of the wall of arteries
2. blood vessel chapter — blood pressure regulation through vasoconstriction and vasodilation
3. urinary system chapter – filtering membrane of the glomerulus in the renal corpuscle
4. development chapter – blood vessels in the placenta

The news item:  Recently the following news item appeared online:

FDA approves groundbreaking blood test for early preeclampsia detection in pregnant women

The FDA has approved a new blood test that can detect whether a mother will potentially get preeclampsia within 30 minutes.

The report describes preeclampsia as high blood pressure in pregnant women, and that in the state of Georgia hypertensive disorders are the leading cause of maternal death. The article describes the name of the test: BRAHMS sFlt1/PlGF KRYPTOR.

So, Why Do I Care??  The death of pregnant mothers is a tragic event that could cause the death of their unborn child as well.  When pregnancy-related high blood pressure appears, the medical response depends on how high the blood pressure is. Once a test predicts that preeclampsia will appear in a pregnant woman, the obstetrician can make preparations for monitoring and further possible actions. When the medical professionals are ready to make treatment choices, it is more  likely that the intervention will be successful, and both mother and baby will survive.

Plain English, Please!!!  First, let’s talk about why high blood pressure appears in pregnant women who had normal blood pressure before the pregnancy. By the end of the first month of pregnancy the fetus builds a placenta, an organ that incorporates a layer of the mother’s uterus as well. The purpose of the placenta to provide a place for exchange of oxygen and nutrients from the blood of the mother to the blood of the fetus, and for the exchange of carbon dioxide and other waste products from the blood of the fetus to the blood of the mother. This can be achieved only if a large number of fetal blood vessels and maternal blood vessels are part of the placenta. In the fetuses where the number of blood vessels is low in the placenta, the fetus will be deficient in oxygen, and the blood vessels release stress factors such as placenta growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt1). Those stress factors reprogram the blood vessels of the mother to contract, and the contracting blood vessels increase blood pressure. Imagine a balloon filled with water. If you squeeze the balloon the force will increase water pressure to the point that balloon may burst. Smooth muscle cells in the wall of arteries do the squeezing (vasoconstriction) that increases blood pressure.

Second, let’s talk about why is preeclampsia harmful. High blood pressure in the mother can cause strokes by dislodging clots from large blood vessels and moving them to the brain where the clots block smaller blood vessels. High blood pressure cause kidney disease by damaging the filtering membrane in the renal corpuscle part of the nephron. Both strokes and kidney disease shorten life expectancy, and may require long-term medical treatment.

Third, let’s talk about what are the markers used in the preeclampsia predicting test. The test is measuring in blood the concentration of PlGF and sFlt1, the very molecules that are released from a stressed placenta.  The larger the stress on the placenta, the more of these stress factors are in the blood, and, thus, the higher the chances of the pregnant woman to develop preeclampsia.