Use-effectiveness and client satisfaction in six centers teaching the Billings Ovulation Method.

Use-effectiveness of the Billings Ovulation Method (OM) is reported for 1139 clients from six centers who were followed for at least 24 months. Method failure rates were 1% when calculated by either Pearl formula or life table analysis. Combined method and user failure rates were 20% when calculated with the Pearl formula, and 16% at 12 months and 23% at 24 months by life table analysis. Pregnancy rates were higher for couples using OM alone, than for couples using OM in combination with additional fertility awareness methods or together with barrier methods. The difference was significant when estimated by the Pearl formula but not when analyzed by the life table. The emotional implications underlying the apparent contradiction between a desire to avoid pregnancy and the deliberate coital use of fertile days are reflected in the differences between method and user failure rates, the high client satisfaction levels reported with "user failure," and 56% continuation rate at 24 months. The will require in-depth exploration.