Long-term recall of time-to-pregnancy

Fertil Steril. 1993 Jul;60(1):99-104. doi: 10.1016/s0015-0282(16)56044-0.


Objective: To validate two versions of a short self-completion questionnaire on time-to-pregnancy.

Design: Information from the questionnaire was compared with concurrently collected data from the same individuals.

Population: Questionnaires were sent to 1,647 women who continue to be followed up by the Oxford Family Planning Association Contraceptive Study. Replies were received from 1,498, a response rate of 91.0%. Successful matching was achieved with 1,392 pregnancies that met the study criteria and that had values of time-to-pregnancy in both data sources. Median recall time was 14 years (interquartile range, 11 to 16 years).

Main outcome measures: At the group level, the frequency distributions of time-to-pregnancy from the two sources are presented as cumulative percentages. At the individual level, the distribution of discrepancies between the sources is tabulated separately for each value of time-to-pregnancy, and accuracy of detection of clinical subfertility is presented (sensitivity and specificity).

Results: At the group level, remarkably good agreement was found between the two sources of information. Digit preference was present to a limited degree. There were no important differences between the two questionnaire versions. At the individual level, some misclassification was evident. For the detection of clinical infertility, sensitivity was 79.9% and specificity was 94.9%.

Conclusions: Short, self-completion questionnaires are remarkably accurate for assessing time-to-pregnancy at a group level. Individual-level misclassification is frequent, but detection of clinical subfertility is fairly accurate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Contraception
  • Female
  • Humans
  • Mental Recall*
  • Pregnancy / statistics & numerical data*
  • Pregnancy Outcome
  • Reproducibility of Results
  • Surveys and Questionnaires*
  • Time Factors