Standing Sex Position Prevent Pregnancy

A case in Java, where a young girl desperate to have sex with a married man. So she was not pregnant, the girl was having sex while standing, aka having sex with a standing position.Is it true that he chose that way?
In principle, pregnancy may occur if there is sperm entering through the vagina and successfully fertilize the egg released during fertile. Outside the fertile women, sexual intercourse is not likely to cause pregnancy. If viewed from a position of sexual intercourse, in any position will still provide the possibility of pregnancy. However, the best position to produce a pregnancy is the man on top, because the sperm is deposited around the mouth of the womb longer.Having sex with a standing position, it allows the sperm to get out again, did not get buried in the vicinity of the mouth of the uterus. Therefore, theoretically, the possibility of pregnancy is small when compared with men in top positions. It's just that, statistically, the possibility of pregnancy still exists. That is, sexual relations with a standing position can not be used as a way to prevent pregnancy.
Sperm that enter through the vagina must be out again. Indeed strange that did not come out again. Remember, sperm cells contained in the fluid spermalah necessary for the occurrence of pregnancy. Sperm cells that move into the uterus for the fertilized egg cell search. (Cy)