The astonishing fertility decline in Iran began around 1985 in the midst of governmental advocacy for more children and four years before the inauguration of the national family planning program by the government [13]. When launched, the family planning program was effective in accelerating the fertility decline by removing social and economic barriers to contraceptive use through making modern contraceptives available free of charge throughout the country. Family planning counseling and services were provided to rural couples through the country’s rural health networks [14]. At the same time, the desire for smaller family size was on the rise [10] and therefore the program enjoyed a high level of social acceptance. The use of modern contraceptives increased from 27% to 57% between 1989 and 2004 [15]. In all, the level and speed of the fertility decline went far beyond the government's original conservative targets [15].

Wow, would you look at that. This entire study goes into the details of the boom and bust of population growth in Iran and what a fucking SHOCKER.

It has to do with reproductive health and family planning and marriage age of women. Other factors as well, but y'all looooove to say it's just a money issue when it's not. It has everything to do with women's freedoms.