Movie mistake

You are right. Doctors say not to quit cigarettes, Xanax, and marijuana so suddenly because it can cause stress to the baby. Even alcohol can be the same, but they will ask you to wean off. But and her situation it seems she does not have an addiction problem with any of these drugs, so quitting wouldn't be any difficultie so quitting wouldn't be difficult after the first day of finding out.

A little line from him saying "You won't be needing these anymore" could've worked in that scene perfectly. sorry for the addon