The Predictive Value Of Down’s Syndrome Screening Serum For Placenta Previa With Placenta Accreta Spectrum Disorders

Background and ObjectiveThe paper herein mainly to explore the values of first and second routine maternal screening serum markers of PAPP-A、AFP、free β-hCG、uE3 and their multiple of median(MOM)on the placenta accrete spectrum(PAS)disorders for placenta previa.And at the last,we would make up an applicative predictive model for clinical working.Study DesignPregnant women who were diagnosed with placenta previa both preoperation and post operation.Including total of 189 patient who were hospitalized for delivery in the obstetrics department of Affiliated Foshan Maternity&Child Healthcare Hospital,Southern Medical University from January 2015 to June 2019 were selected.According to whether complicate with PAS disorders,these women can be divided into placenta previa with PAS disorders group and without PAS disorders group.Clinical characteristic,first and second serum index of screening markers include the reality value of PAPP-A、AFP、first and second free β-hCG、uE3 and the multiple of median(MOM)levels and imaging diagnosis would be recorded and retrospectively analyzed the association between the two group.Univariate and multivariate logistic regression analyses were used to identify serum indexes that were associated with PAS disorders for placenta previa.Nomogram were constructed based on regression coefficients.Internal validation were applied to assess the performance of the model.ResultThe results showed that the serum of first trimester free β-hCG MoM and uE3 MoM in PAS group was statistical higher than the non-PAS group(P<0.05).AFP in PAS group was statistical lower than the non-PAS group(P<0.05).Univariate logistic regression analyses show that the sensitivity to diagnose PAS disorders of first trimester free β-hCG and its MoM,uE3 MoM were respectively 51%,64%,57%.The specificity were respectively 65%,54%,64%.The accuracy of diagnose were respectively 57%,60%,60%.The diagnose threshold were 64.34 ng/ml,1.12,0.97 respectively,and the area under the ROC curve(AUC)were 0.57,0.6,0.6 respectively.The sensitivity to diagnose PAS disorders of decrease in AFP was 77%,the specificity was 46%,the accuracy of diagnose was 63%,the diagnose threshold was 53.99 U/ml and the AUC was 0.62.Because of the fewer variables,the P<0.1 were included in multivariate logistic regression analyses,and show that the increase of the first trimester free β-hCG and its MoM,uE3 MoM were independent risk factor for PAS disorders.However the AFP had no statistical differences(P>0.05).Combine the serum index to make up two predictable model.These two model show the sensitivity were 76%,37%respectively,the specificity were 47%,87%respectively,the accuracy of diagnose were 63%,59%respectively,the AUC were 0.65,0.67.Validating the model through bootstrap and the calibrated AUC were 0.63,0.65.The model from the similar study has an AUC of 0.62.ConclusionsThe serum of first and second trimester Down’s syndrome may has a certain effect in predicting placenta accreta spectrum disorders for placenta previa.The combination of AFP,first trimester free β-hCG and its MoM value,uE3 MoM value can certain improve the early identification.More studies are required.