Causes of fetal choroid plexus cysts

For pregnant women, nothing is more important than the health of their fetus. A healthy fetus means hope for the family. But life is magical and full of twists and turns. For example, many pregnant women are found to have fetal choroidal cysts during pregnancy checkups. So what are fetal choroidal cysts? Why would pregnant women be diagnosed with fetal choroid cysts? What should we do if this situation occurs?

Choroid plexus cyst refers to small cysts with a diameter of ≥3 mm that are found scattered in the choroid plexus of the fetus' lateral ventricle during fetal development during gestational age of 14 to 24 weeks through ultrasound examination. The fetal choroid plexus is mainly formed around the seventh week of pregnancy and is the main place where the fetus produces cerebrospinal fluid. Around the 10th to 16th week of pregnancy, the choroid villi will grow rapidly and occupy most of the lateral ventricles. At this time, the loose choroid villi will contain part of the cerebrospinal fluid and form a cyst-like structure, which is what is clinically called a fetal choroid plexus cyst.

Are fetal choroid plexus cysts common?

Abnormalities found during examinations are of course something that expectant mothers are particularly worried about, so the question of whether fetal choroid plexus cysts are common is naturally something they are particularly concerned about. Around 19 to 26 weeks of pregnancy, the loose structure of the choroid plexus will gradually be replaced by dense connective tissue. Therefore, the fetal choroid plexus cyst will probably disappear before 26 weeks of pregnancy. This situation is also very common among fetuses. Therefore, generally speaking, expectant mothers do not need to worry too much after discovering the problem of fetal choroid plexus cyst after examination.

Even a normal fetus may have choroid plexus cysts. Generally speaking, most of them will disappear before 26 weeks. In this way, there will be no brain compression or increased intracranial pressure, and the intelligence will not be affected after birth. However, a small number of choroid plexus cysts may persist into childhood and may easily obstruct cerebrospinal fluid, leading to acute hydrocephalus in the child. It is recommended to perform an acute brain examination and a chromosome examination of the umbilical cord blood cells after the baby is born.

What causes choroid plexus cysts?

Choroid plexus cysts are cerebrospinal fluid-filled pseudocysts that appear within the choroid plexus. They are caused by the fact that the rate of cerebrospinal fluid production during the development of the fetal brain primordium is higher than the rate of development of the brain aqueduct. When the production of fetal cerebrospinal fluid is faster than the formation of the aqueduct system in the brain, it will cause a certain degree of cerebrospinal fluid circulation obstruction or formation of choroid plexus cysts. However, the fetus usually forms a brain aqueduct system around 26 weeks. Therefore, once the drainage system is formed, the circulation problem will be solved, the accumulated fluid will gradually disappear, and the cyst will also disappear. If it has not disappeared and is bilateral, the fetus may have chromosomal diseases such as trisomy 21 or trisomy 18, and amniocentesis or cord blood puncture is needed to rule out chromosomal abnormalities.