How well do women recall past contraceptive use? A pilot study

Many women use a variety of contraceptive methods during their reproductive lives. Investigating this exposure is one of the most frequently performed epidemiological investigations. Accurate recall of methods used, as well as validating this information, can be difficult. A pilot study compared recalled contraceptive use over 5 years with that documented in the case notes of 30 women.

47% of episodes of method use were accurately recalled to the month of starting method use; this figure rose to 94% when episodes with disagreement within +/-12 months were also considered. Similarly, 44% and 91% of episodes were accurately recalled to the month and within +/-12 months of stopping method use, respectively. Accuracy of recall for duration of use followed a similar pattern. 7% of users were unable to distinguish between use of a combined pill and a progestogen-only pill and one-third of women using an intrauterine contraceptive were unable to distinguish an intrauterine device (IUD) from the intrauterine system (IUS).

Almost all women can recall accurately which contraceptive methods they have used in the past year but are less accurate in respect of exact starting and stopping dates. Some women confuse the combined pill with the progestogen-only pill and others confuse the IUD and the IUS. The findings need to be replicated in other settings and with populations of less well-educated women.