Circumvallate placenta is an abnormality in the shape of the placenta. It can result in a lack of nutrients for the fetus. In circumvallate placenta, the chorionic plate, which is the part of the placenta that’s on the fetal side, is too small. That causes the membranes to double back on the fetal side and around the edges. The condition can be detected by ultrasound and is usually diagnosed around the 20th week of pregnancy. However, diagnosis during pregnancy can be difficult and the condition is often not detected until the placenta is examined following delivery. Circumvallate placenta is extremely rare, occurring in around 1 to 7 percent of pregnancies. https://www.healthline.com/health/pregnancy/circumvallate-placenta#:~:text=In%20circumvallate%20placenta%2C%20the%20chorionic,20th%20week%20of%20pregnancy.
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