Which of the following describes a "deformation" in the context of prenatal development?

A "deformation" in the context of prenatal development refers to a structural abnormality that arises due to extrinsic factors, primarily environmental influences that affect the developing fetus. These influences can include factors such as mechanical forces, maternal health conditions, or nutritional deficiencies that alter the normal development of the fetus.

Deformations typically occur when a normal structure is altered due to these external pressures or conditions, rather than being caused by genetic abnormalities. An example might be a situation where oligohydramnios (insufficient amniotic fluid) leads to limb deformities due to compression during fetal development.

This emphasizes the importance of understanding how environmental factors can interfere with structural development, differentiating deformations from other types of abnormalities that are primarily intrinsic or genetic in nature. The distinction between these concepts is crucial for maternal-fetal medicine practitioners in assessing risks and managing prenatal care.