Validity of Different Methods to Prenatal Screening for Down’s Syndrom During First and Second Trimester Pregnancy of Chinese Women

Objective To identify and determine the optimal method to screening for fetal Down＇s syndrome （DS）. Methods Three large cohorts with 17 118, 39 903, 16 646 subjects were enrolled for the first trimester double marker （pregnancy-associated plasma protein A and free [B-human chorionic gonadotropin） screening （FTDMS）, second trimester double marker （c{-fetoprotein and free B-human chorionic gonadotropin） screening （STDMS）, and second trimester triple marker （a-fetoprotein, free 13-human chorionic gonadotropin and unconjugated estriol 3） screening （STTMS）, respectively. The sensitivity, specificity, false positive rate （FPR）, false negative rate （FNR） and the areas under ROC curves （AUCs） were estimated in order to determine the optimal screening method in women under or above 35 years old. Results For women under 35 years old, STTMS was the best method with a detection rate of 68.8% and FPR of 4.3% followed by the STDMS with a detection rate （sensitivity） of 66.7% and FPR of 4.9%. The FTDMS had a lower detection rate of 61.1% and FPR of 6.3%. For women above 35 years old, the detection rate of all the methods was similar, but STTMS method had a lowest FPR of 15.9%. For women under 35 years old AUCs were 0.77 （95% CI, 0.64 to 0.91）, 0.81 （95% CI, 0.71 to 0.91）, and 0.82 （95% CI, 0.69 to 0.96） for FTDMS, STDMS, and STTMS methods, respectively; for those above 35 years old, AUCs were 0.70 （95% CI, 0.56 to 0.83）, 0.70 （95% CI, 0.59 to 0.82）, 0.78 （95% Cl, 0.58 to 0.97） for FTDMS, STDMS and SITMS, respectively. Conclusion Findings from our study revealed that STDMS is optimal for the detection of fetal DS in pregnant women aged under 35. For individual women, if economic condition permits, STFMS is the best choice, while for women aged above 35, STTMS is the best choice in this regard.

Genetic counseling, prenatal screening and diagnosis of Down syndrome in the second trimester in women of advanced maternal age： a prospective study

Background The incidence of autosomal trisomy in livebirths is strongly dependent on maternal age. Special consideration is given to the provision of prenatal screening and cytogenetic testing to women of advanced maternal age （AMA）. The aim of this study was to evaluate the effectiveness of second trimester prenatal screening and amniocentesis for Down syndrome （DS） and compare the trends of choice of screening and amniocentesis among AMA women. Methods A total of 5404 AMA patients with natural singleton pregnancy were recruited for this prospective study from January 2008 to December 2010. The gestational weeks were from 15 weeks to 20~6 weeks. The patients referred were grouped into a screening group （2107 cases） and an amniocentesis group （3297 cases） by their own decision. The prevalence of DS was compared between the two groups by chi-square test. Choice rates for each maternal age with trends were compared by regression analysis. Results There were 18 cases of fetal DS detected in the screening group with a prevalence of 8.54%o （18/2107）. Twenty- five cases of fetal DS were diagnosed in the amniocentesis group with a prevalence of 7,58%0 （25/3297）. No statistical difference was observed in the prevalence of DS between the screening and amniocentesis group （P=0.928）. The invasive testing rate for DS in the amniocentesis group was 5.54 times higher than that of the screening group （1/131.88 vs. 1/23.78）. With the increase of the maternal age, the choice of amniocentesis increased while the choice of the screening showed an opposite trend. The choice of the AMA women between the screening and amniocentesis was significantly age relevant （P=0.012）. Conclusions The second trimester serum screening age alone to screen for DS. We suggest educating screening and amniocentesis options. in combination with maternal age was more effective than maternal the patients by recommending AMA women be informed of both

Two factors affecting the success rate of the second non-invasive prenatal screening after initial no-call result: experience from a single tertiary center in China

Background:One inevitable shortcoming of non-invasive prenatal screening(NIPS)/cell-free DNA(cfDNA)sequencing is the uninterpretable(“no-call”)result,which is mainly caused by an insufficient fetal fraction.This study was performed to investigate the factors associated with a successful second NIPS in these cases and determine the optimal management for women with initial no-call results.Methods:We retrospectively analyzed the data of women who underwent NIPS with initial no-call results due to an insufficient fetal fraction from 2017 to 2019 in our center.We compared these women's maternal and pregnancy information with the data of women who had attained a successful second NIPS result and women who had received no-call results for a second time.Results:Among the 33,684 women who underwent NIPS,137 with a no-call result underwent a retest.Comparison between the 87(63.50%)women with a successful retest and the other 50(36.50%)women showed a significant difference in both the initial fetal fraction and maternal body mass index(BMI),whereas the other factors showed no significant differences.In addition,with an initial fetal fraction of<2.00%,the retest success rate was very limited.Conclusions:We identified two major factors associated with a successful NIPS retest:the initial fetal fraction and the maternal BMI.These findings suggest the need for specialized management for this subset of women and would be instructional for the counseling for these women.

Application of intelligent algorithms in Down syndrome screening during second trimester pregnancy

BACKGROUND Down syndrome(DS)is one of the most common chromosomal aneuploidy diseases.Prenatal screening and diagnostic tests can aid the early diagnosis,appropriate management of these fetuses,and give parents an informed choice about whether or not to terminate a pregnancy.In recent years,investigations have been conducted to achieve a high detection rate(DR)and reduce the false positive rate(FPR).Hospitals have accumulated large numbers of screened cases.However,artificial intelligence methods are rarely used in the risk assessment of prenatal screening for DS.AIM To use a support vector machine algorithm,classification and regression tree algorithm,and AdaBoost algorithm in machine learning for modeling and analysis of prenatal DS screening.METHODS The dataset was from the Center for Prenatal Diagnosis at the First Hospital of Jilin University.We designed and developed intelligent algorithms based on the synthetic minority over-sampling technique(SMOTE)-Tomek and adaptive synthetic sampling over-sampling techniques to preprocess the dataset of prenatal screening information.The machine learning model was then established.Finally,the feasibility of artificial intelligence algorithms in DS screening evaluation is discussed.RESULTS The database contained 31 DS diagnosed cases,accounting for 0.03%of all patients.The dataset showed a large difference between the numbers of DS affected and non-affected cases.A combination of over-sampling and undersampling techniques can greatly increase the performance of the algorithm at processing non-balanced datasets.As the number of iterations increases,the combination of the classification and regression tree algorithm and the SMOTETomek over-sampling technique can obtain a high DR while keeping the FPR to a minimum.CONCLUSION The support vector machine algorithm and the classification and regression tree algorithm achieved good results on the DS screening dataset.When the T21 risk cutoff value was set to 270,machine learning methods had a higher DR and a lower FPR than statistical methods.

Current situation and development of prenatal diagnosis in China

Prenatal screening and diagnosis are major methods for control of birth defects,which is a very important problem in China.Here,we review current situation and development of prenatal screening and diagnosis in China's Mainland,including prenatal screening and prenatal diagnosis of fetal chromosome abnormalities,non-invasive prenatal diagnostic techniques and prenatal diagnosis of monogenic diseases,polygenic disease and congenital metabolic diseases.We also discuss epidemiology of birth defects and genetic diseases in China and related ethical issues of prenatal diagnosis.

Comparison of second-trimester maternal serum free-p-human chorionic gonadotropin and a-fetoprotein between normal singleton and twin pregnancies： a population-based study

Background The second-trimester maternal serum screening in twin pregnancy is still controversial, as the serum marker levels in twins are not as clear as those in singletons. This study aimed to evaluate the relationship between the levels of the second-trimester maternal serum free β-human chorionic gonadotropin （free β-HCG） and a-fetoprotein （AFP） in normal twin and singleton pregnancies and to estimate feasible analysis methods for utilizing these markers in second trimester screening for twin pregnancy. Methods On the basis of a prospective population-based study of second-trimester maternal serum screening, the concentrations of maternal serum AFP and free β-HCG of 195 normal twin pregnancy and 26 512 singleton controls at gestational weeks 15 to 20 were measured by time-resolved fluoroimmunoassay in one laboratory. The levels of markers were compared between the twins and singletons using weight-correction and gestational age-specific model. Results According to the research protocol, 95 communities were randomly sampled, which covered the whole Jiangsu province, the east of China. A total of 26 803 pregnant women （98%）, from the target population accepted prenatal screening for maternal serum AFP, β-HCG detection, and all babies were followed up for at least six months. There were 197 （0.73%） twin pregnancies, of which one case had fetal trisomy 18, and one case with fetal anencephaly. The others were normal twin pregnancy. From a total enrollment of 26 803 women participants, 26 512 women with normal singleton pregnancies were selected as the model controls. The other 291 pregnancies, including trisomy 21, neural tube defect （NTD）, trisomy 18, and other fetal abnormalities, were excluded. No significant differences were found in the medians of gestational age-specific maternal serum free β-hCG and AFP in normal twin pregnancy comparing with twice those in model controls with the exception of the medians for free β-hCG during the 16th gestational week （P=0.012）. Conclusion The weight-correction and gestational age-specific levels of Chinese Han population maternal serum free β-hCG and AFP in normal twins were twice the levels as those in the singleton controls during the 17-19 gestational weeks.