Which of the following is NOT a type of decidua during pregnancy?

Decidua is the term used to describe the modified mucosal lining of the uterus during pregnancy. It plays a crucial role in supporting the developing embryo and later, the fetus. The types of decidua include:

• Decidua basalis, which is the area of the decidua that lies beneath the implanted embryo and contributes to the placenta.

• Decidua capsularis, which surrounds the gestational sac and eventually becomes part of the placental membrane as the embryo grows.

• Decidua parietalis, which refers to the remaining portion of the decidua lining the uterine cavity that does not come into direct contact with the placenta.

The other option, decidua myometrium, is not a recognized type of decidua. The myometrium is the muscular layer of the uterus, distinct from the decidual tissue, and does not function in the same capacity during pregnancy. Therefore, identifying decidua myometrium as not being a type aligns with the understanding of decidua in the context of pregnancy and uterine anatomy.