The same "dry up" shot was given to my aunt. In that day (about 53 years ago) in Alberta it was not the norm to breastfeed. But my dad's mom was insistent with the daughter-in-laws (my mom & aunt) that they must breastfeed. My aunt remembers trying and trying to breastfeed but it wasn't working -- only be find out that the pills that she had been taking in hospital included one for drying up the milk. She hadn't thought to ask what the pills were and she had informed the staff that she was going to breastfeed. So yes, that type of thing did happen.