药物使用对胎儿畸形的影响是一个复杂的问题。许多药物都可以穿过胎盘，直接影响发育中的胎儿。此外，不同阶段的胎儿对药物的反应也有所不同。因此，医生会极力避免在怀孕期间使用药物，特别是前三个月，这是胎儿器官发育最为活跃的阶段。
That being said， there are some medications that have been proven to cause birth defects. For example， thalidomide was a medication that was used to treat morning sickness in the 1950s and 1960s. However， it was later found to cause limb deformities and other birth defects in babies whose mothers took the drug during pregnancy. This tragedy led to stricter regulations on drug testing and approval.
In addition， certain medications like retinoids， which are used to treat acne and other skin conditions， are known to cause birth defects if taken during pregnancy. Other medications， like certain antidepressants or anticonvulsants， may also increase the risk of birth defects. However， it is important to note that the decision to use medication during pregnancy should be made on a case-by-case basis， with careful consideration of the potential risks and benefits.
Ultimately， the best course of action for pregnant women is to avoid using any medications unless absolutely necessary， and to always consult with their healthcare provider before taking any medications or supplements. With proper precautions， it is possible to minimize the risk of birth defects and ensure a healthy pregnancy and baby.
