It won’t affect the legal paperwork of the adoption. You do need to share with Adoption Coordinator what type of drugs were used during the pregnancy. It will affect the unborn baby. It’s always best for the baby as it develops to be drug free. What you use goes to the baby.
There are always families available to adopt babies who were exposed to both alcohol and drugs, but in order to provide your baby with the best care, they need honest information. This enables them to prepare now, and be prepared later should challenges arise.
There are also families who are willing to adopt babies born who go through withdrawal symptoms at birth. The benefit to choosing an open adoption prior to delivery is that you and the mother can stay in touch, get updates, and know where your child is. If you do not make a plan prior to birth and drugs are found in the baby, often the child is removed by Child Protective Services and you do not have the opportunity for any ongoing contact whatsoever.
If you need help with trying to stop, ask for help. Take it one day at time.