These methods work better for women whose cycles are always the same length. Some couples chart the woman s fertility pattern to prevent pregnancy because it is economical, safe, and can be discontinued easily when pregnancy is desired. Little equipment is needed, and calendars, thermometers, and charts are widely available. No medication is involved, which is especially appealing to women who have physical or health conditions that might make other forms of birth control less desirable or unsuitable. Medical checkups are not required, although professional instruction is important.
Periodic abstinence is acceptable to most religious groups.
However, if a couple decides to have vaginal intercourse during the fertile period, pregnancy is likely to occur unless they use barrier methods such as a combination of condom and foam. Charting fertility patterns requires dedication, education, and practice. It is most effective when both partners are mature, responsible, and committed to making them work. That s why it is very important for both partners to learn the fundamentals and support each other in observing the abstinence or contraceptive use that is required. Women who are breastfeeding or approaching menopause may find it more difficult to chart their fertility.