Discordance between self-reported contraceptive use and detection of exogenous hormones among Malawian women enrolling in a randomized clinical trial.

OBJECTIVE: The objective was to assess the extent of concordance between self-reported contraceptive use and the presence of contraceptive progestins in serum.

STUDY DESIGN: We evaluated self-reported contraceptive use by using radioimmunoassay to examine baseline serum levels of medroxyprogesterone acetate (MPA) and levonorgestrel (LNG) among 97 Malawian women enrolling in a contraceptive trial.

RESULTS: Twelve percent (12/97) of study participants who reported no hormonal contraceptive use in the previous 6months had either MPA or LNG detected in their serum.

CONCLUSIONS: The observed discordance between self-report and detection of exogenous hormones in serum indicates that caution is warranted when drawing conclusions based on self-reported contraceptive use.