Abstract
A decline in annual acceptances in a contraceptive programme is open to multiple interpretation. The decline may reflect an adverse change of attitudes and therefore a lowered disposition to accept the method among couples of the population generally. Alternatively, if the population has an irregular age distribution, the decline may mean only that the numbers of couples of prime contraceptive age have temporarily dropped. Thirdly, if the rate of previous acceptance has been high, the main cause of a slackening in new acceptances may simply be that previous acceptances have partially depleted the pool of eligible couples. Fewer eligible couples are left than previously as a consequence of past acceptance, removing couples interested in contraception faster than the family-building process can create new ones.