i dont understand. are you asking if contractions occur after sex. and that answer is yes sex can cause contractions because the sperm has a checimal tthat reacts with your cervix and mucus inside your cervix
Semen has prostaglandins, it just softens your cervix. It doesn't cause contractions. What does cause contractions are orgasms. And orgasm is basically a contraction. Sex in general can cause contractions because your cervix is sensitive during pregnancy, and it can also cause spotting. It's ok to have sex, but if you're bleeding a lot, or have really bad cramping it might be best to wait and ask the dr.