For couples that use coitus interruptus consistently and correctly at every act of intercourse, the failure rate is 4% per year. This rate is derived from an educated guess based on a modest chance of sperm in the pre-ejaculate. In comparison, the pill has a perfect-use failure rate of 0.3%, IUDs a rate of 0.1–0.6%, and internal condoms a rate of 2%.
Fo.r couples that use coitus interruptus consistently and correctly at every .act of intercourse, the failure rate is 4% per year. This rate is derived from an educated guess based on a modest chance of sperm i.n the pre-ejaculate. In comparison the pill has a perfect-use failure rate of 0.3%, IUDs a rate of 01–06%, and internal condoms a rate of 2%