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Periodic abstinence during fertile periods
Most effective when intercourse restricted to postovular phase of cycle or barrier method used at other times
Women should identify fertile periods (see Infertility, Female)
However, comparative efficacy trials of these methods against other contraceptive methods do not exist
"Symptothermal" natural family planning
Patient-observed increase in clear elastic cervical mucus, brief abdominal midcycle discomfort ("mittelschmerz"), and sustained rise in basal body temperature about 2 weeks after onset of menstruation
Unprotected intercourse is avoided from shortly after the menstrual period until 48 hours after ovulation, as identified by a sustained rise in temperature and the disappearance of clear elastic mucus
Basal body temperature method shows the safe time for intercourse after ovulation has passed
Take temperature immediately upon awakening, before any activity
A slight drop in temperature often occurs 12–24 hours before ovulation, and a rise of about 0.4°C occurs 1–2 days after ovulation
The risk of pregnancy increases starting 5 days prior to the day of ovulation, peaks on the day prior to ovulation, and then rapidly decreases to zero by the day after ovulation
The standard days method
Uses a set of beads to remind the couple to avoid intercourse during days 8 through 19 of the cycle
Typical use failure rate is 12%
Applicable to women with a history of menstrual cycles between 29 and 32 days