In perinatology "Outcome" is almost always defined in terms of mortality or serious morbidity. Evaluation of care for normal pregnancy and midwifery care in particular cannot rely only on outcome measures per se, but must also take the means and interventions by which these are achieved into account. Perinatal Background and Perinatal Outcome Indexes were developed for the assessment of midwifery care in women with low-risk pregnancies. These indexes were applied in a prospective study of midwifery care during labor and childbirth for a population of 1836 women with low-risk pregnancies in The Netherlands. The Perinatal Background Index confirmed that the study population was indeed a population at low risk of perinatal complications. The Perinatal Outcome Index gave an adequate description of both the result and process of childbirth, with a lower score indicating a further deviation from the optimal situation of "maximum outcome with minimal intervention."