Yes it does, which is why it is considered back-up contraception. The JP insititue for life and family has documentation proving this as does Human Life International and all other right to life organizations. This is why they opposed it.
It is also why Catholic hospitals were forbidden to prescribe it to rape victims, if they were unable to determine if the vicim had ovulated or not.
Is it back up if a woman takes 2 birth control pills after having unprotected sex because the woman missed the day before?