As far as I know there is no test that can show that. And as thetam said, nothing can show how many times you had relations with any particular person, or how many times period. However, if you have had previous pregnancies and are now pregnant again, it is important to let your Dr. know. Don't worry, they keep it confidental, but they do need to know. Do not feel ashamed or embarrassed. If your Dr. is judgemental, find a new Dr.
Good luck to you.
after u get pregnant, ur cervical opening looks a little different and sometimes theres a little scar tissue or wall thickening in the area of a previous pregnancy. but after u have intercourse once ,they cant tell how many times u actually had relations. u need to share with ur doctor about previous pregnancy because u could have biult antibodies in ur blood