The 1982 census enumerated a population of slightly more than 3 million. Demographers suggested annual growth rates from 2.5 to 2.9 % in the late 1980s. Thus, in mid-1988, estimates of total population ranged from 4 to 4.4 million. Assuming a yearly increase of between 2.5 and 2.9 % until the end of the century, Paraguay would have a population of 5 to 6 million by the year 2000.

The average age at which Paraguayan women entered their first marriage or consensual union began to rise in the 1950s. By the late 1970s, women in Asunción averaged 19.7 years of age at their first marriage; those in other cities were about 8 months younger and those in rural areas were a year younger. The Ministry of Public Health and Social Welfare cooperated in the family-planning efforts of a number of international agencies active in the nation and managed several family- planning clinics in Asunción and other parts of the nation. Between 1959 and 1978, the total fertility rate--an estimate of the average number of children a woman will bear during her reproductive years--declined by nearly one-third, to 4.97. Estimates put the rate at 4.6 in the mid-1980s, with 3.4 projected by the turn of the century.