Effect of Changes in Response Options on Reported Pregnancy Intentions: A Natural Experiment in the United States

Abstract

Objectives: The Pregnancy Risk Assessment Monitoring System (PRAMS), conducted by the Centers for Disease Control and Prevention in collaboration with state health departments, is the largest state-level surveillance system that includes a question on the intention status of pregnancies leading to live birth. In 2012, the question was changed to include an additional response option describing uncertainty before the pregnancy about the desire for pregnancy. This analysis investigated how this additional response option affected women's responses.

Methods: We used the change in the pregnancy intention question in 2012 as a natural experiment, taking advantage of relatively stable distributions of pregnancy intentions during short periods of time in states. Using PRAMS data from 2009-2014 (N = 222 781), we used a regression discontinuity-in-time design to test for differences in the proportion of women choosing each response option in the periods before and after the question change.

Results: During 2012-2014, 13%-15% of women chose the new response option, "I wasn't sure what I wanted." The addition of the new response option substantially affected distributions of pregnancy intentions, drawing responses away from all answer choices except "I wanted to be pregnant then." Effects were not uniform across age, parity, or race/ethnicity or across states.

Conclusions: These effects could influence estimated levels and trends of the proportion of births that are characterized as intended, mistimed, or unwanted, as well as estimates of differences between demographic groups. These findings will help to inform new strategies for measuring pregnancy and childbearing desires among women.

Keywords: PRAMS; measurement; pregnancy intention; survey methods.

Figure 1

Percentage distribution of responses among women to the pregnancy intention question for each year of the Pregnancy Risk Assessment Monitoring System (PRAMS) survey, 2009-2014. The question asked was, “Thinking back to just before you got pregnant with your new baby, how did you feel about becoming pregnant? (Check one answer.)” Beginning in 2012, PRAMS added a fifth response option to the core pregnancy intention question: “I wasn’t sure what I wanted.” Data source: Shulman et al.

Figure 2

Percentages of women reporting “I wasn’t sure what I wanted,” adjusted for state and year of survey, by maternal age, by maternal race/ethnicity, and by number of previous live births, Pregnancy Risk Assessment Monitoring System survey, 2012-2014. The question asked was, “Thinking back to just before you got pregnant with your new baby, how did you feel about becoming pregnant? (Check one answer.)” A, By maternal age. B, By race/ethnicity. C, By number of previous live births. Error bars indicate 95% confidence intervals. Data source: Shulman et al.

Figure 3

Predicted treatment effects by age, race/ethnicity, and parity, Pregnancy Risk Assessment Monitoring System (PRAMS) survey, 2012-2014. The question asked was, “Thinking back to just before you got pregnant with your new baby, how did you feel about becoming pregnant? (Check one answer.)” Beginning in 2012, PRAMS added a fifth response option to the core pregnancy intention question: “I wasn’t sure what I wanted.” The average treatment effect for each category of demographic characteristic (eg, age group) can be interpreted as the predicted effect of the question change on the log odds of women in that group choosing the specified response category relative to the log odds that women with that same characteristic would have chosen it in the survey periods before the question change. Error bars indicate 95% confidence intervals. Data source: Shulman et al.

Figure 4

Predicted treatment effect among states with data for all years of the study period, Pregnancy Risk Assessment Monitoring System (PRAMS) survey, 2012-2014. The question asked was, “Thinking back to just before you got pregnant with your new baby, how did you feel about becoming pregnant? (Check one answer.)” Beginning in 2012, PRAMS added a fifth response option to the core pregnancy intention question: “I wasn’t sure what I wanted.” The average treatment effect for each state can be interpreted as the predicted effect of the question change on the log odds of women in that state choosing the specified response category relative to the log odds that women in that same state would have chosen it in the survey periods before the question change. Error bars indicate 95% confidence intervals. Data source: Shulman et al.