Natural family planning
There are several ways of predicting the fertile time of your cycle using observations of vaginal mucus, timing of your menstrual cycle and body temperature. You then avoid sex during this time. Natural family planning usually involves using one or all of these approaches in combination and could be used to plan pregnancy. Use of natural family planning requires motivation from both partners but does suit some women at some times in their lives.
You can also look at the Fertility UK website for useful charts and information about planning and avoiding pregnancy using other natural family planning methods.
The following link provides a comparison of all the various different contraceptive methods https://www.nhs.uk/conditions/contraception/