Why coitus interruptus is not full proffed method of contraception?

tomab5: Why coitus interruptus is not full proffed method of contraception?
It for an anatomy class..plese answer this..

Answers and Views:

Answer by Sugar boobs
Because sperm can thrive in the fallopian tubes for up to five days.

OR

“Pull out and pray” just does not work.

Answer by naenae0011
You can still get pregnant from pre-cum.

Answer by Crazy Horse
Because the male ejaculate seeps out prior to orgasm and since the little critters are olympic swimmers, just a tad goes a long way.

Answer by PurplePrincess
google : https://en.wikipedia.org/wiki/Coitus_interruptus

IE: Pull out method does not work for preventing pregnancy

Answer by April A
because there could be sperm in the pre c*um which the man does not feel come out or he may not pull out in time and some semen may get into the vagina. in either one of those circumstances a woman could then become pregnant.

Answer by Surprise!!
Before fully ejaculating, men ejaculate a small amount of sperm known as pre ejaculate and there is no feeling that occurs so there is no way to know that its there. This pre ejaculate contains sperm which can impregnate a woman.

Answer by Gail D
Because pre-ejaculate contains the most potent sperm.

Answer by mommy_2_liam
pre-ejaculate contains semen…so it can still get you pregnant.