If you’re not 100% sure you’ll avoid sex on all of your fertile days, you should definitely be using another method in addition to fertility awareness-based methods. If you prefer to avoid hormones, you can use condoms (male or female), a diaphragm or cervical cap with spermicide, or the sponge.
Still not working?
If you and your partner are having trouble sticking to the fertility awareness-based methods schedule but you want a non-hormonal method, you might want to consider the ParaGard IUD. It’s non-hormonal and super low-maintenance.