Risk Factors in Embryonic Development

Understanding the prenatal stages of development is crucial for recognizing how environmental factors can influence fetal growth. During the embryonic stage, which lasts from the third to the eighth week of pregnancy, many vital processes occur that are essential for proper development. A variety of factors can negatively impact this stage, leading to complications.

Which of the following factors is most likely to result in a significant risk to normal development during the embryonic stage of prenatal development?