VP06.08: The application of late amniocentesis: a retrospective study in a tertiary fetal medicine centre in China

To assess the indications and complications of late amniocentesis, as well as the advantagement of advanced genetic test results. In this retrospective study, women that underwent amniocentesis at 24+0 to 39+4 weeks, between January 2014 and June 2019, were recruited. Indications, complications, genetic test results and pregnancy outcomes were reported for each pregnancy. Information was obtained from case records, validated by research staff and analysed by using SPSS 21. In the cohort, 1243 pregnancies (1272 fetuses), including 1154 singleton pregnancies, 85 twin pregnancies, and two triplet pregnancies, underwent late amniocentesis in our centre. CMA was performed in all these cases, while traditional karyotype was performed in 678 (53.3%) cases, and MES or WES was performed in 12 (0.9%) cases. Late detected abnormal ultrasound finding(s) (88.3%) comes to be the most common indication. PTB rate and IUD rates were 3.1% and 1.7% separately. Sixty-six fetuses with aneuploidy (5.2%) and Sixty-seven others with a pathogenic copy number variants (5.3%) were identified by CMA, while one pathogenic copy number change (8.3%) were reported via WES. The diagnostic yield turned to maximal (31%, 35/113) in the sub-group of fetuses with suspected prenatal diagnosis results, following by combination of ultrasound findings (23.1%, 25/108). Since CMA, MES and WES have considerable detection rates, it is reasonable to serve late amniocentesis as an effective and safe method to detect fetal abnormalities or reassure parents following late detected abnormal ultrasound findings. However, A percentage of CMA and ES may expose uncertain results like VOUS. Therefore, comprehensive genetic counseling is necessary.