Contraception is any method used to lower the chance of pregnancy. The list runs from condoms and diaphragms to pills, implants, IUDs, injections, fertility-awareness routines, vasectomy, and tubal procedures. Effectiveness numbers assume the method is used as designed, which humans only sometimes manage.

Hormonal methods change ovulation or mucus. Devices occupy the uterus or block sperm. Permanent methods cut or close the pipes. Emergency contraception exists for the broken-condom night and is not a plan for every Monday.

STI protection is a separate question. Only barriers do much of that work. A copper IUD can be a superb pregnancy block and still leave viral risk untouched.

The best method is the one a person will actually use and can get, afford, and tolerate. That sentence annoys manufacturers and saves pregnancies.