Objective The central aim of this study was to assess the feasibility of the developed adverse outcome registration method. Furthermore, it was tested whether the information gathered through the... Show moreObjective The central aim of this study was to assess the feasibility of the developed adverse outcome registration method. Furthermore, it was tested whether the information gathered through the registration system allowed for comparative analyses. Design Prospective observational multicentre study. Setting The obstetrics and gynaecology departments of three Dutch university and three general hospitals. Population Every consecutive admission to these departments during the 12-month study period. Methods All complications, during admission and up to 6 weeks after discharge, were registered using a standardised form. The complication type and origin were noted and the severity of the complications were graded. Main outcome measures The differences in relative frequencies of complications between the participating university and general hospitals. Results A total of 10 470 admissions were observed at the obstetrics and gynaecology departments of the six hospitals combined. The standard complication registration form was completed for approximately 90% of these admissions. A total of 351 gynaecological (9.1%) and 960 obstetrical (14.5%) complications were reported. There was no significant difference in the percentage of complications between general hospitals and university hospitals. The severity of complications, however, varied significantly between the participating hospitals. Conclusions A feasible framework for complication registration in the field of obstetrics and gynaecology has been developed. Before comparing frequencies of adverse events between hospitals, such outcome measures first need to be risk-adjusted to overcome the problem of patient variation and acuity between hospitals as a source of difference, leaving quality of care as a primary source of variation. Show less