What is the seminal exposition among women requiring emergency contraception? A prospective, observational comparative study

In one-third of the women presenting for EC, no sperm were identified in the vagina. When sperm were present, the number was much lower than that after intercourse among women wishing to conceive. The risk of an unwanted pregnancy is probably, therefore, lower for women who present for EC compared with that for women who truly have unprotected intercourse.