What virus is associated with congenital malformations during pregnancy?

The rubella virus is known to be associated with congenital malformations during pregnancy, particularly when infection occurs in the first trimester. Maternal infection can lead to a condition known as congenital rubella syndrome (CRS), which can cause serious consequences for the developing fetus. These may include a range of debilitating birth defects such as cardiac defects, cataracts, deafness, and growth retardation.

The teratogenic effects of rubella are primarily linked to the timing of the maternal infection. If a woman contracts rubella early in her pregnancy, the likelihood of these congenital malformations significantly increases, as the virus can affect organ development during critical periods of fetal growth.

Other viruses, such as those causing hepatitis, may also have implications for maternal health and can impact babies, but they are not primarily associated with congenital malformations in the same way that rubella is. Thus, rubella stands out as the virus with a well-documented history of causing severe birth defects when maternal infection occurs during pregnancy.