Pregnant and Large Lecturing?

I know this seems like a silly concern, but I'd genuinely appreciate some advice from those who have been in this position before...

Fall semester begins soon, just as I'll be entering my second trimester. I suspect students won't be able to tell for the first couple weeks, but I will certainly start showing as the semester progresses. (Based on my incredibly increased consumption of fast food fries, my belly is going to be noticeable. And soon.)

I have two courses: one a large lecture (about 100 students, a mix of majors and non-majors) and one a much smaller seminar. I'm not concerned about the seminar at all. (Given the course content and size of the class, I'm very comfortable sharing personal material like this.) My issue is with the large lecture... Normally I keep my private life very separate from my professor persona, especially in large lectures. Sure, I aspire to be approachable and reinforce my humanity because, wow, students can forget profs are people, too. However, students don't need to know the details of my personal life. I take pride in how I've drawn this line in past years.

Herein lies the question: Do I just announce at the start of the term that I'm pregnant to the class? I suspect this will explain any unusual behaviors that might emerge (e.g., bathroom breaks needed in the middle of lecture, occasional needs to sit down even though that's not my delivery style at all, my fry-induced pregnant belly growing quickly in front of them, possible ninja moves from the kiddo while trying to get through denser theory)...but it's not relevant to the material in any way and I don't want the inevitable handful of students to then weaponize this against me when they're mad at their earned grades on a subject or annoyed by course content. At the same time, it's weird to never acknowledge the soon-to-be obvious, right?

Important details: This is my first pregnancy. Course evaluations do matter for my role and in my department, and this class's evals will be a part of my dossier when I go up for full in a few years. Also, the class itself is somewhat controversial (I mean, it shouldn't be, but what a world we live in).

Any advice? Things that worked well for you (or didn't)?