OBJECTIVES: To determine whether contraceptive discontinuation is associated with pregnancies that are conceived earlier than desired (mistimed) or are not wanted at the time of conception (unwanted). METHODS: Data were obtained from the 2002 Guatemala National Maternal and Child Health Survey. Pregnancies within the three years prior to and at the time of the survey (April 1999-November 2002) were classified as either "intended," "mistimed," or "unwanted." The key independent variable was whether the woman had used contraception within 12 months of the pregnancy and, for those who had used it, the reason for discontinuation (either to get pregnant or for another reason). A multinomial logistic analysis was used to determine the degree of association of discontinuation with pregnancy intentions. RESULTS: One of every five mistimed pregnancies and one of every six unwanted pregnancies followed discontinuations that were for reasons other than to become pregnant (e.g., contraceptive failure, side effects, and health concerns). Discontinuations for reasons other than to become pregnant were shown to be positively and significantly associated with a reported mistimed pregnancy (coefficient = 2.15; standard error = 0.27) or unwanted pregnancy (2.68; 0.37) compared to an intended pregnancy. Pregnancies preceded by discontinuations for reasons other than to become pregnant were also more likely to be reported as mistimed or unwanted than pregnancies of women who were not using contraception during the year prior to pregnancy. CONCLUSIONS: There is a need to increase contraceptive continuation. Any program should include an increased effort to reduce contraceptive failure and better address the side effects and the health concerns that women have that can lead to discontinuation. Non-users who want to delay or limit births should also be identified and targeted for outreach in order to reduce unintended pregnancies.