Why is coitus interruptus (withdrawal method) not recommended?

Withdrawal (coitus interruptus), as a natural contraceptive method, often fails to achieve effective contraception. During sexual intercourse, when sexual excitement reaches its peak, small amounts of semen may be released into the vagina due to contractions of the vas deferens. Although the volume of this pre-ejaculate fluid is minimal, it can contain a large number of sperm, making pregnancy quite likely. The interruption of ejaculation can cause psychological stress and anxiety in men, leading to diminished sexual function. Some individuals may develop symptoms such as premature ejaculation, or even erectile dysfunction.