i wouldn't recommend the sponge. before the "new" one came out my mom used it about 21 years ago. guess how old my brother is. lol.
to answer your question straight up.....NO
nothing is ever 100% when it comes to preventing pregnancy...
The pill, IUD are the ones that i would suggest, but for that your GF has to see a GYN...
The New Sponge is also available without prescription at you local drugstore...following the directions accurately it is a good method to prevent pregnancy, but not a fool proof one and not 100% reliable...
if you want to loose the condom your GF has to go on one of the above mentioned methods in order to be safe from pregnancy but not from STD .
Hope it helped a little bit!!!
even if you pull out "correctly" she can still end up pregnant. pre ejaculate is produced throughout any sexual act and it DOES contain sperm which CAN get her pregnant. if she isn't pregnant already you're lucky.
the ONLY ways to prevent pregnancy are b/c pills, shot, patch, iud and/or condoms (b/c alone is NOT 100% effective and does fail. many many women have ended up pregnant while on b/c) OR not having sex until you're ready for the consequences...i.e. a child and/or std's.