They are all safe. Your body kinda tells you when it's not okay. Kinda like sleeping on my stomach, I did it until my body said stop so now I don't do it anymore. As for sex, at the end when you are the biggest it may be hard to do missionary it always was for me so hands and knees always worked better that last week or 2. Top worked too but I just didn't feel so sexy being that huge and on top but don't let that discourage you, you do what works for you.