So this is running on XOJane today:
and though I know what I am about to say about is going to be a seriously unpopular opinion, I'm going to say it anyway: I don't automatically give up my seat to pregnant women, nor do I think I should be expected to. This is an active and political choice.
I am a young, able bodied woman and sometimes and I adhere to a pretty militant subway code. I don't expect men to give up their seats for me by virtue of my having a vagina in my possession. I don't expect that other people are going to be able to tell by looking at me when I have had a super long day that I need their seat. Basically I don't expect that any human being on the subway is going to prioritize me over themselves. On the other side of the coin, I try to be really reasonable when offering my seat to other people. If someone, man or woman, old or young, looks to me might they might be really tired ( I have what I am sure are flawed methods for determining this) I might offer my seat to them if I'm not feeling tired. If someone has a super exasperated look on their face and has been jostled several times and I feel like I'm more up to fighting the jostling battle than they are, I give up my seat. I always give up my seat to someone who needs a standing or walking aid like a cane— because subway surfing can be straight up dangerous if you have trouble moving without support. The only other people that I always give up my seat to are small children, because, well a lot of times they just don't get it or a parent who might have two small children who can't stand on their own.
In short, there are some days when I don't mind giving up my seat and I will offer it to anyone who looks like they might enjoy taking a seat or who might really need to take a break from standing. But there are days when I've got my own stuff to deal with, when I've gotten like two hours of sleep, where I'm pissed off, where I'm fighting back tears and although the pregnant women who are expecting me to give up my seat on the subway can't see it from looking at me, I might need the seat more than they do. I think pregnancy is awesome. I hope to be pregnant one day, and I know that there will be days when I have uncomfortable side-effects and I'll wish that someone would give up their seat for me on the subway. I might even get a little huffy and give out some side-eye. But will I write an article about how rude they were for not giving up their seat? Nope. Because they won' t owe me that because I'm pregnant and my life and the other life that depends on me won't necessarily be more important than theirs.
Though I know pregnancy isn't always a choice for the woman carrying the child, it certainly wasn't a choice for the random subway riders around her. I do think it's okay if a pregnant woman wants to ask me for my seat, but I also think it's okay for me to look her in the face and say "no, I need this seat more today for reasons you might not be able to see."
ETA: I clearly didn't articulate this well or think to include it the first time, but I certainly always give up my seat if I am in one of the seats that requires that patrons do that by law. I also think it's unclear from this post that I am someone who OFTEN gives up my seat because I recognize that most people need it more than I do. However, as a person who is expected unfairly to give of myself to others on a daily basis because of a lot of weird classist, racist, and sexist societal expectations, it can be frustrating to be asked to do this after a long day of serving other people when I'm just trying to get my ass home. It can be especially frustrating when this happens at the stops in the wealthiest neighborhoods.