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.
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