masturbating

Hi everyone..so possibly a tmi for some...but I have a best friend who is 31wks pregnant. She's not on any groups or anything because her boyfriend is a bit of a control freak with her & any kind of social media 😒🙄 Anyways, she asked me a question but I didn't know the answer so i decided to come to all of you hoping for an answer. She has been masturbating using a hairbrush paddle....is that safe? I didn't want to give her false information so I flat out said idk. But maybe someone else has experience with this. 😊 please no judgement. She's not a very open person when it comes to her private sexual life but she was concerned for the safety of the baby which is why she's asking here before she asks her doctor...