Uterus starts to get firm in 3rd trimester
By bump was not completely hard at all times and all positions (laying down,sitting) until about 26-27 weeks. I thought it was hard waaaay before then but then it really got hard lol. I'm 33 weeks and now can barley crawl into my SUV BC my tummy is rock hard!
Mine started at 12 weeks. I've got a small bump, but I can feel that my stomach has tightened internally. It's sort of weird. Similar to tightened muscles, but there's no feeling with it besides it being a little hard.