When someone starts a new hormonal method of birth control (like the Depo shot), it takes 1 week for the hormones to be integrated enough into the body to start preventing pregnancy.
Once the Depo shot is at full effectiveness, the Depo shot is preventing pregnancy by up to 99% for 3 months. But in order for the Depo to consistently be effective, you need to make sure you’re getting the shot every 3 months.
Because this was the first time you’d gotten the shot and you had unprotected sex 4 days into the week, you were not protected from pregnancy during the first week and are at risk of pregnancy. You have the option of taking Plan B (emergency contraception) for up to 5 days after unprotected sex. It’s important to note though that the sooner you take emergency contraception, the more effective it will be.
But the only way you will know for sure if you’re pregnant is to take a pregnancy test. You can take a pregnancy test 14 days after unprotected sex and at that time you will get an accurate result.
If you have more questions, give us a call at 303-442-5160 to make an appointment or to talk with a provider.