During which period of development is the unborn baby MOST AT RISK of developing a structural defect because of the effects of a teratogen?

Question

Quizplus · Accepted Answer

During the embryonic period (weeks 3-8), the developing embryo is most vulnerable to the effects of teratogens. This is the period when the major organs and systems are forming, and any disruption to this process can result in structural defects or other abnormalities. The fetal period (week 9 to birth) is still a critical time for development, but most major organ systems have already formed by this point. Teratogens can still have an impact on growth and function during the fetal period, but the risk of structural defects is reduced. The germinal period (first two weeks after conception) is too early for teratogens to have a significant impact, and any damage during this time is more likely to cause the pregnancy to end in miscarriage or fail to implant. At conception, teratogens cannot have any effect since fertilization has not yet occurred.

During Which Period of Development Is the Unborn Baby MOST