You can get free emergency contraception, also known as Plan B or the morning-after pill, at a clinic especially for teens. These pills can prevent pregnancy after unprotected sex or birth control failure.
You can get sexual health services at a clinic without your parents' permission or knowledge. Services are confidential, free or very low-cost, and open to all. You will be helped regardless of your immigration status.
If you are 17 or over, you can also buy emergency contraception at the drug store. A pilot program in some NYC public high schools offers emergency contraception and other reproductive health services.