What are the dangers of rotaform placenta?

Wheel-shaped placenta generally refers to the deformity of the embryo shape. Wheel-shaped placenta is divided into two categories: complete type and partial type. Generally, partial type of wheel-shaped placenta is not easy to cause abnormalities in the fetus, so there is no risk, and it will not have any abnormal adverse effects on the pregnant woman herself. Only the complete type of wheeled placenta may cause placental abruption, even premature birth, and may also cause risks such as fetal malformations. Therefore, for complete wheel-shaped placenta, cesarean section is generally considered to terminate the pregnancy.

The incidence of rotund placenta is less than 1/6,000. It refers to the concave center of the fetal surface of the embryo, surrounded by a thickened gray ring. The ring is composed of bifolded amnion and chorion, with degenerated decidua and fiber in between. Inside the ring, the fetal face is a normal shape and is attached to the fetal umbilical cord. Large blood vessels can be seen ending at the edge of the ring, and the rolled and thickened amniotic villi often cause embryonic bleeding and infarction. Wheel-shaped placenta can be divided into two categories: complete type (forming a complete ring of embryonic tissue) and partial type (forming an incomplete ring of embryonic tissue). Partial type wheel-shaped placenta does not cause any fetal abnormalities, while complete type wheel-shaped placenta is associated with placental abruption, prematurity, IUGR, fetal malformations, and increased perinatal mortality, but complete type wheel-shaped placenta is rare. The dysmorphic sonographic changes of the wheel-shaped placenta are that the edge of the embryo protrudes into the amniotic cavity in a ring-shaped strip or block-like shape, and the internal echo is similar to the intrinsic echo of the embryo. If there is bleeding or infarction, there may be anechoic or low-echo areas inside. Wheel-shaped placenta, especially the edge of the embryo protruding into the amniotic cavity in a ring-shaped strip, has similarities with amniotic band syndrome in the sonogram, which is easy to cause misdiagnosis. The two should be carefully distinguished.

Ultrasound diagnosis:

1. The sonographic changes of the dysmorphic placenta are that the edge of the embryo protrudes into the amniotic cavity in a ring or block shape, and the internal echo is similar to the intrinsic echo of the embryo. If there is bleeding or infarction, there may be no echo or low echo area inside.

2. The camera performs a radial scan of the embryo, that is, a 360-degree observation of the edge of the embryo, which is helpful in assessing the degree of rotund placenta. For example, in the posterior placenta, due to the influence of the embryo, information may not be displayed and misdiagnosis may occur.