Coitus interruptus consists of removing the penis from the vagina before ejaculation, so that no sperm are deposited in or around the vagina. This is an unreliable contraceptive method because:
About half the men who have tried coitus interruptus find it unsatisfactory because they don't know when they are going to ejaculate or because they can't withdraw fast enough.
More importantly, during sexual arousal, pre-ejaculatory fluid is emitted from the Cowper's gland, two pea-sized structures located on each side of the urethra. This pre-ejaculatory fluid appears as drops on the tip of the penis any time from arousal and erection to orgasm. This fluid can contain active sperm, which can lead to pregnancy even with withdrawal prior to ejaculation.
Hudson Health Center Athens, Ohio 45701 T: (740) 593-1660