According to Planned Parenthood, a woman can get pregnant using the withdrawal method. Planned Parenthood notes that up to 27 out of 100 women who rely on this method of birth control risk becoming pregnant each year.
The Mayo Clinic explains that the withdrawal method of birth control, also known as coitus interruptus, involves a man withdrawing his penis from his partner's vagina and moving it away from her genitals prior to ejaculation.
The Mayo Clinic goes on to say that this method of birth control requires high levels of self-control and is not particularly effective. Pre-ejaculation fluid sometimes contains sperm, and sperm can enter the vagina if the man fails to withdraw his penis in a timely manner, according to the Mayo Clinic. In addition, the Mayo Clinic warns that this method of birth control does not offer any protection from sexually transmitted diseases.