| Objective: To evaluate effectiveness of one stop clinic for assessment of risk(OSCAR) for chromosomal abnormality screening by maternal age, fetel nuchal translucency(NT), free β human chorionic gonadotropin(Fβ-hCG) and pregnancy-associated plasma protein-A(PAPP-A) as well as to establish the medians of Fβ-hCG and PAPP-A at11+0-13+6gestation weeks in Mainland Chinese pregnant women.Methods:1. OSCAR chromosomal abnormality screening was conducted in4886pregnant women in the first trimester by maternal age, NT, Fβ-hCG and PAPP-A in the1st Affiliated Hospital of Kunming Medical University, China between May7,2012to Oct09,2013. The data of pregnancy characteristics were recorded at booking, fetal NT and crown-rump length (CRL)were measured using the guideline of Fetal Medicine Foundation (FMF) in UK and maternal Fβ-hCG and PAPP-A were measured by chemiluminescence simultaneously. All the sonographers have been certificated by FMF. Quality control for NT and laboratory measurements were audited at regular intervals by FMF, and the United Kingdom National External Quality Assessment (UKNEQAS), respectively. Both NT and biochemical measurements were converted into multiple of the medians (MoM) and adjusted for maternal weights, smoking status, single and multiple pregnancy and method of conception.2. The patient specific risk of trisomy21,18and13were calculated using OSCAR screening software for Fetal Medicine Center of Chinese University of Hong Kong. The high risk cut-off was1/600and the range of risk betweenl/600and1/1600was regarded as intermediate risk. Amniocentesis was performed for high risk cases and non-invasive prenatal testing (NIPT) was recommended for intermediate risk cases.3. All the women who had the screening were followed up for pregnancy outcomes. Effectiveness of OSCAR screening were evaluated by detection rate (DR)、 and false positive rate (FPR).4. The best fit equation of the median of maternal Fβ-hCG and PAPP-A measurements against getational days was established by regression curves in3,781women who were non-smoking nulliparous singleton pregnancy with normal outcomes.Results:1.4886patients were screened by OSCAR during the study period. The mean of maternal age was29.29±3.85years. The outcomes of4717cases (96.29%,4717/4886) were available by following up. The total of152(3.22%,152/4886) cases had adverse outcomes.2. There were13cases with chromosomal abnormalities (including6cases of trisomy21,2cases of trisomy18,4cases of other chromosomal abnormalities,1case of XYY syndrome who had an intermediate risk).3. The FPR of OSCAR was5.89%, and DR for trisomy21,18,13and total chromosomal abnormalities was100%and92.31%, respectively.4. For those with intermediate risk, the DR of chromosomal abnormalities can be effectively increase by NIPT.5. No pregnancy loss after amniocentesis in the second trimester was found during this study period.6. The incidence of birth defects was1.00%(47/4717) in the study population.7. The best fit equations of Fβ-hCG and PAPP-A concentration against gestational days was Median Free β-hCG=70.42+0.142*day-0.00005907*day3; Median PAPP-A=e(-4.424+0.068*day) respectively.Conclusion:1. OSCAR screening in first trimester is as highly effective, safe and cost effective for Maniland Chinese women as in Hong Kong. Quality control by regular audit for USG and laboratory assessment must be warrented.2. The medians of Fβ-hCG and PAPP-A in Kunming population were established. |
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