Validation of a prognostic model for adverse perinatal health outcomes.

There is a strong association between social deprivation and adverse perinatal health outcomes, but related risk factors receive little attention in current antenatal risk selection. To increase awareness of healthcare professionals for these risk factors, a model for antenatal risk surveillance and care was developed in The Netherlands, called the 'Rotterdam Reproductive Risk Reduction' (R4U) scorecard. The aim of this study was to validate the R4U-scorecard. This study was conducted using external, prospective data from thirty-two midwifery practices, and fifteen hospitals in The Netherlands. The main outcome measures were the discrimination of the prognostic models for the probability of a pregnant woman developing adverse pregnancy outcomes (babies born preterm or small for gestational age), and calibration. We performed cross-validation and updated the model using statistical re-estimation of all predictors. 1752 participants were included, of whom 282 (16%) had one of the predefined adverse outcomes. The discriminative value of the original scoring system was poor [area under the curve (AUC) of 0.58 (95% CI 0.53-0.64)]. The model showed moderate calibration. The updated R4U-scorecard showed good generalisability to the validation set but did not alter the predictive value [AUC 0.61 (95% CI 0.56-0.66)]. By using external data and by updating the prognostic model, we have provided a comprehensive evaluation of the R4U-scorecard. Further improvement in classification of high-risk pregnancies is important considering the necessity of early risk detection for healthcare professionals to take appropriate actions to prevent these risks from becoming manifest problems.