Women with a strong desire to avoid pregnancy are significantly more likely to use contraceptives consistently than are women who regard pregnancy avoidance as less important. However, women’s attitudes toward pregnancy and, in turn, their contraceptive use can change in a relatively short period of time, according to "Using Longitudinal Data to Understand Changes in Consistent Contraceptive Use," by Rachel K. Jones, of the Guttmacher Institute, et al. While the majority of women studied (82%) had a strong desire to avoid pregnancy at some point during the 18-month study period, just 41% had a consistently strong desire across the entire period, and 53% reported a change in their attitude toward pregnancy.

Inconsistent contraceptive use or nonuse accounts for 95% of unintended pregnancies in the United States, yet little is known about how changes in women’s context affect contraceptive use. To explore this question, between November 2012 and May 2014, researchers collected four waves of data from 1,842 U.S. women who were aged 18–39 at baseline. Women were asked about their contraceptive use and attitudes toward pregnancy and contraception, as well as their life circumstances, sexual activity and access to health care.

"A woman’s risk of unintended pregnancy is often treated as a stable characteristic," says Jones. "Our study shows that a woman’s risk of pregnancy, along with her contraceptive use, can change over a relatively short period of time. Her feelings about having a child, as well as her sexual activity, can fluctuate, and those fluctuations can influence how much she prioritizes contraception."

The majority of the study participants were considered at risk of unintended pregnancy during each survey period, yet only 42% were at risk during all four, largely because of changes in their plans to have children or sexual inactivity. Similarly, only 45% of participants were consistent contraceptive users across the entire study, although a high proportion (84–85%) of those at risk reported consistent use of contraceptives at each survey.

The study’s findings highlight the importance of service providers’ offering information and access to a broad range of methods. This would best support the contraceptive needs of women and couples as their fertility intentions change over time.

"Using Longitudinal Data to Understand Changes in Consistent Contraceptive Use," by Rachel K. Jones, et al., is currently available online and will appear in a forthcoming issue of Perspectives on Sexual and Reproductive Health.