I was pregnant and working in Singapore and had a long commute. Although people are generally polite, they become like beasts on public transport.
I had one situation where I got on and everyone (well, 4 out of 6 in the row) sat had been texting or reading, but then suddenly developed narcolepsy and pretended to be asleep.
Another where a family had all their 5 children (ranging 4-ish to 8ish sat in front of me) and stared up and me and pointed at my belly for the whole journey.
Best one was when I was changing lines to a busier line on the underground and waiting to get on and some behind me had been nudging me in the back and then tried to push past me and failing that flung his newspaper through the gap over my head as the person was vacating a seat in order to 'chope' it before I could get to it. Promptly did, picked up paper and then fell asleep. Choping, by the way, is reserving tables in restaurants/food centre with a packet of tissues and is REALLY PASSIVE AND ANNOYING.
The only thing I can say is I was altogether a less rational, more leery person, wanting to avoid public confrontation when I was pregnant, so if I was unsure of the reception I'd not risk any argy bargy.
I also had a sedentary job so didn't mind standing quite so much.