Researchers conducted this study to examine the long-term effectiveness and continuation of the Standard Days Method. The method works best for women with processes usually in the range of 26–32 days, which is a fundamental reason for method discontinuation in the first year of use. The authors determine if this continues to be an issue in the second and third years of the method used.

Participants in an earlier efficacy study and method introduction studies were followed for two years beyond the original 1-year study period to determine their continued use of the method, intended and unintended pregnancies, and reasons for discontinuation.

The method continues to be effective in the second and third years of use and compares favorably to other user-directed family planning methods. Women with no more than two cycles within a year are likely to continue having processes within this range.

The study concluded that women who complete the first year of SDM use are likely to continue to use the method successfully and effectively. The technique presents a viable longer-term option for women who prefer this approach to family planning.