Determining the Fertile Window when Preventing Pregnancy with the Sympto-thermal Method
This person is using the sympto-thermal method of fertility awareness for pregnancy prevention. If they follows all of the rules properly, they must either abstain from intercourse or use a back-up method of birth control starting on cycle day 11 (when cervical fluid is first noticed), until cycle day 19, when the rules have been satisfied. Since this person's period lasted only five days, they are not considered fertile until cycle day 11, when cervical fluid appears. Since they experienced a sudden temperature shift, they can consider themselves infertile starting in the evening on cycle day 19, in accordance with the Double-Check Rule.
Learn the rules of the sympto-thermal method of fertility awareness.