Pregnant or Not??

Have you ever given up your seat on the a train to a pregnant woman/ old person or disabled person?

This morning as I was taking the train to work, a lady walked in and stood in front of me. She looks young and was wearing a baby doll top with capris and it looks like she has a little baby bump. But I was not 100% sure if she is pregnant... The bump was not too big and she is not really thin in other areas so it is very difficult to tell if indeed she is pregnant or she is just a little plump. If I gave up my seat  and she is not pregnant, she would feel really bad that she looks pregnant to others (I think every girl will feel like crap if this happens) so I was in a dilemma.

Where I live, there are many ways out of this kinda situation, usually people (a) close their eyes and pretend they are sleeping, (b) take out a book, newspaper, flyer etc and pretend they are reading and didn't notice or (c) have really thick skin and pretend they didn't see them. Such is the case this morning on the train. Three people beside me were sleeping, one was reading a newspaper and one was facing the other side talking on her cellphone. So it is up to me to decide if I want to give up my seat but I really could not decide then what I should do.

I clearly remember an incident a year ago at my friend's wedding when I asked an acquaintance when is her baby due and she replied me bitterly "I'm not pregnant, I'm just fat'... I think that incident can be classified as one of the most embarrassing moments of my life so I was thinking if I want to risk it again. As I was considering my options, an old lady walked in and I quickly gave up my seat to her. That saves me the trouble of deciding if lady A is pregnant or not.