What is it? When having sex, the man has to take his penis out of the vagina before ejaculation. This is intended to stop sperm from entering the woman.
Considerations: this method frequently fails as drops of sperm can already escape from the penis into the vagina before the man ejaculates.
How effective? Failure rate can be as high as 15% (15 pregnancies per 100 women). More reliable methods are advised.