Strengths and limitations
One of the main strengths of the study includes the prospective enrolment of patients. Additionally, this study was performed within the context of routine clinical practice and patients were seen by their usual physicians, making the results more reliable and applicable in routine care settings. Furthermore, this is the first study assessing the performance of the FMF algorithm exclusively in a Spanish cohort and in a clinical setting where MAP was measured once and only in one arm, showing comparable results to those reported in the original study. Despite a previous study showed that prediction of PE is similar when biomarkers are measured before or after 11 weeks6, the FMF algorithm was designed with biomarkers assessed between 11+0 and 13+6 weeks. In this study biomarkers were measured before 11+0 weeks in 1,675 (63.4%) women. Therefore, another remarkable strength of our work is that it provides evidence of the applicability of the FMF and Gaussian algorithms before and after 11 weeks for predicting PE and SGA.
The main limitation of our study is the low number of cases with early-onset SGA and early-onset PE, and the relatively low number of cases with preterm SGA and preterm PE. Additionally, indication for elective delivery of SGA fetuses based on Doppler and cardiotocogram findings may be different when using other fetal growth restriction protocols. However, Doppler and cardiotocogram classification is rather uniform in Spain, where the Gaussian algorithm is widely used. Another limitation to be noted is that the technique for MAP measurements may potentially reduce the FMF algorithm’s performance and could explain its lower AUC versus the Gaussian algorithm for some marker combinations.