While abortion rates usually decline with increasing usage of modern contraceptives (Westoff, 2005, Shah and Ahman, 2004), they may rise due to a strong desire for smaller family size during periods of rapid fertility decline. Studies have shown an association between fertility transition and unwanted pregnancy in some developing countries, indicating a rise in unwanted pregnancies during the fertility transition, and remaining relatively high until the end of the transition period (Bankole and Westoff, 1995, Bongaarts, 2002). Contrary to other countries, the substantial fertility decline in the Islamic Republic of Iran has been accompanied by only a moderate rise in the age at first birth, which increased from 18.5 years in the 1980s to 21 years in the 1990s (Abbasi-Shavazi and Hosseini-Chavoshi, 2014).