The first trimester of pregnancy is the time of greatest risk for fetal defects and abnormalities of the embryo and fetus caused by teratogens.

Question

Quizplus · Accepted Answer

During the first trimester, the major organs and systems of the fetus are being formed, making them particularly vulnerable to the negative effects of teratogens. This is why it is important for pregnant women to avoid exposure to known teratogens during this time.

The First Trimester of Pregnancy Is the Time of Greatest