April 24, 2014 — While there has been little change in the typical age when women have sex for the first time over the past several decades, women born in the early 1980s wait much longer until their first marriage and first birth compared with those born about 40 years prior, according to a new study from the Guttmacher Institute.
As a result, women today face a greater number of years when they likely wish to avoid pregnancy and need effective contraception.
The researchers used federal data on women born from 1938 through 1995, grouping the data into birth cohorts for analysis. They calculated women's median age for various reproductive events -- such as first menstrual period, first sex and first birth -- and assessed how they changed over time.
The median age at first sex declined for women born in the 1950s and 1960s, but it later increased again, surpassing 17 years for women born in the early 1980s. Meanwhile, the typical time between first sex and first birth widened overall over time, reaching nearly 10 years for women born in 1982.
The study also showed that the gap between when women first have sex and start using contraception has narrowed, which means a lower risk of unintended pregnancy.
At the same time, the longer time that women need contraception before their first births underscores the importance of access to reliable birth control, particularly long-acting, highly effective methods like the intrauterine device or contraceptive implant, according to the researchers.
Data sources: "Trends in Ages at Key Reproductive Transitions in the United States, 1951-2010," Finer/Philbin, Women's Health Issues, April 12, 2014.
Guttmacher Institute release, April 10, 2014.