The shot offers slightly better pregnancy prevention — 6 in every 100 people who receive it will become pregnant in the first year. The pill offers similar protection, with 9 in every 100 people becoming pregnant in their first year of taking the pill.
However, both methods are only effective if the person follows recommendations for taking them. A person taking the pill needs to take it at the same time every day, while a person receiving the shot will need to schedule appointments with a healthcare professional every 3 months to maintain their protection.
If a person does not follow the schedule, they have a higher risk of becoming pregnant. A person can also use barrier methods, such as condoms, in combination with the pill or the shot, for further protection.