How good is oral contraceptives in preventing pregnancy?

More than 99%: The regular birth control pill is more than 99% effective if you take it correctly. In other words, less than 1 out of 100 women each year become pregnant if they take it right. The mini-pill or progesterone-only pill is about 95% effective if you take it right. So about 5 out of 100 women each year become pregnant if they take the mini-pill right. Hope this helps!

Excellent, but...: With no missed pills, "perfect use", the failure rate is 0.3%=>99% effective.In typical use, because taking a pill every d without ever missing is hard, about 9/100 couples will get pregnant/year. If you have a hard time remembering daily meds, ask your doctor about long-acting reversible contraception(larc)--iuds or an implant under the skin-easy, very effective, lasts 3-10 yrs.