Use of drugs during pregnancy should be made after a medical advice only. Some drugs are good to be taken during pregnancy while some should be strictly avoided. Thus, it is always advisable to take an advice from the doctor before consuming any drug.
Use of drug during pregnancy is avoided because drugs cross the placenta and reach the fetus. This can lead to serious implications such as
1. abnormal development of the fetus
2. underdeveloped or underweight babies
3. babies with drug dependency