is your mum even saying she was offended or just talking about the difference between then and now? Because yes, until very recently, it WAS considered unacceptable to show off a pregnant belly. There was a huge hoo hah when some minor celebrity (might have been Nikki Buckley) carried on working on Sale of the Century and wore dresses that showed off rather than hid her belly.

Just ask her straight out whether she was offended rather than reading that into what she said.