Monitoring maternity services by postal questionnaire: congruity between mothers' reports and their obstetric records.

The validity of information obtained from women about the medical aspects of their childbearing experiences has been assessed by comparing the responses of 223 mothers on a postal questionnaire with information extracted from their medical records. When discrepancies between the two sources were found, it was not assumed that the hospital records were correct. Instead, attempts were made to ascertain why the data might be inconsistent by re-checking the records and by contacting the mothers again. There appeared to be five main reasons for discrepancies: mothers' limited knowledge or understanding of certain procedures; problems of interpretation and definition; occasionally inaccurate or missing information in the medical records; under-reporting of sensitive information by mothers and, finally, questions which were misunderstood or misinterpreted by the mothers. For most items, however, good agreement between the mothers and hospitals was obtained, and the results indicate that valid information over a range of events can be obtained using postal surveys of mothers.