When is medication exposure likely to occur during pregnancy?

Medication exposure during pregnancy is particularly crucial to consider before the awareness of pregnancy. Many women may not know they are pregnant in the early weeks. This can lead to situations where a woman continues to take prescribed medications or over-the-counter drugs that may not be safe during pregnancy. During this time, when conception has occurred but pregnancy has not yet been confirmed, the developing fetus can be exposed to potentially harmful substances.

The early weeks of pregnancy, specifically the period when the embryo is developing, are significant since organogenesis—where major structures and organs are formed—occurs shortly after conception. Therefore, any exposure to pharmacological agents during this time can have implications for fetal development.

The other options highlight stages of pregnancy and labor but do not emphasize the critical period immediately following conception when women may be unaware of their pregnancy status. Therefore, understanding this timing is essential for healthcare providers to adequately advise expectant mothers about medication use and its potential effects on fetal health.