What You May Experience After Intercourse
You may feel your uterus contract or increased fetal activity after orgasm. In fact, uterine contractions can last for up to 30 minutes after intercourse for some women. These contractions and movements are perfectly normal and you don't need to worry about them affecting the baby.
Due to increased blood volume and engorgement, your cervix may bleed slightly after intercourse. So don't worry if you see a bit of blood, particularly in the last trimester.