1. Mechanism of action.
a. This method depends on the awareness of the physiology of the male and female reproductive tracts.
b. Sperm and ovum life spans are as follows:
(1) Sperm viability averages 3 days; however, the range is 2 to 7 days.
(2) Ovum life span is about 24 hours.
c. The unsafe period is considered to be up to 7 days before ovulation and 3 days after ovulation.
d. Avoid intercourse at these unsafe times or use other methods such as barriers for backup.
2. Effectiveness rate.
a. There is a 20% failure rate for typical use in the first year.
b. Perfect use has a failure rate of 1% to 9%.
c. The most effective version is the postovulation method.
d. If used perfectly, the symptothermal and ovulation method is very effective.
e. The calendar method is the least effective.
3. Types include the postovulation method, the symptothermal method, the ovulation method, and the calendar method.
(1) Cervical mucus basal body temperature (thermal) is measured.
(2) Lower abdominal pain with ovulation is experienced (symptom).
(3) Perfect use: Intercourse can be resumed only on the fourth day peak mucus and the third day after thermal rise.
b. Ovulation method (Billings method)
(1) Mucus is checked from the vagina before urination.
(2) Mucus is checked for lubrication, elasticity, wetness, and tackiness (it ferns midcycle).
(3) Ovulation occurs 1 day before, after, or during the last day of the most slippery and abundant mucus.
(4) The fertile period is any time mucus is noted before ovulation.
(5) Note: Some women have very insignificant mucus discharges at ovulation time.
c. Basal body temperature (BBT) charting (temperature method)
(1) Body temperature is taken every morning.
(2) The temperature is charted on a BBT chart.
(3) Look for a biphasic temperature chart (Fig. 5-6).
(4) However, 6 out of 30 women ovulate but do not have biphasic changes on a temperature chart.
a. There are no side effects.
b Some couples like to be totally involved in fertility prevention.
a. There is no protection against sexually transmitted diseases.
b. The male partner sometimes objects to participating.
c. It is not as reliable a method of contraception with women who have irregular cycles, recent menarche, approaching menopause, or who are unable to keep records.