Women should not urinate before sex to reduce the risk of developing a urinary tract infection (UTI).
According to one expert, this piece of advice, commonly heard among women, could even increase the chances of getting one. New York City urologist David Kaufman explained the idea females should pee before intercourse is one of the biggest misconceptions he has to address with patients in his clinic.

He stresses that urinating after sex is important, but warns going to the bathroom beforehand is not advisable. Indeed, he told Yahoo News that this mistake ‘is the No.1 cause of post-coital urinary tract infections, also known as honeymoon cystitis’.
Why shouldn’t you wee before sex? During intercourse, bacteria from the vagina can get pushed into the urethra. Waiting to pee, and consequently having enough urine stored up to create a strong stream, increases the odds of pushing that bacteria back out.