How Does the Contraceptive Patch Prevent Pregnancy?
The contraceptive patch is relatively new, so typical rates of effectiveness are not known. The perfect rate of effectiveness is expected to be 99%, which is slightly higher than the effectiveness of birth control pills. The contraceptive patch prevents pregnancy the same way that birth control pills do. It works primarily by preventing ovulation, which means that the ovary does not release an egg to be fertilized. The patch also causes changes to the cervical mucus (making it more difficult for sperm to enter the uterus). The contraceptive patch keeps you from becoming pregnant by delivering continuous levels of hormones through the skin and into the bloodstream. This is called transdermal administration.
