Once you’ve started taking a hormonal method of birth control, you will have to abstain or use a back-up method (like condoms) for one week until it will be effective in preventing pregnancy. It takes one week for the hormones to “kick in” and be effective in preventing pregnancy.
If you are taking your hormonal method correctly and consistently, you will be up to 99% protected from pregnancy. If you are not taking it correctly however, effectiveness will go down. With the Mirena IUD, using it correctly would mean having it changed every 5 years.
In conclusion, if your boyfriend ejaculates inside of you but you’re taking your birth control correctly, you will be up to 99% protected from pregnancy. It’s always a good idea to use some type of barrier method (like condoms) in addition to a hormonal method of birth control to help reduce the risk of STI transmission. If you have additional questions, give us a call at 303-442-5160.