Browsing by Author "Järvelä, Josephine"

Trisomy 21 (Down syndrome) is the most common aneuploidy seen in newborns and it is associated with advanced maternal age. Screening for trisomy 21 in twin pregnancies is advisable but more complex than in singletons. First trimester combined test screening is well-established and widely accepted as part of first line screening method in singletons, however, the performance of first trimester combined test in twin pregnancies has achieved less attention and only scarce data is available on its performance. The aim is to describe the performance of first trimester combined test in twin pregnancies in our Finnish cohort. This study is a retrospective cohort study of twin pregnancies registered in Helsinki University Hospital area during January 2014 – November 2017. Data was collected from Fetal Medicine Department and patient medical records. A fetus-specific risk assessment was calculated based on biochemistry in addition to nuchal translucency and maternal age. 661 twin pregnancies were included of which 174 (26.3%) were monochorionic and 487 (73.6%) dichorionic pregnancies. Six trisomy 21 cases were identified in our cohort with a pregnancy-specific prevalence of 0.6%. First trimester screening combined assessment using cut-off 1/250 for high risk achieved fetus-specific DR 83.3% (95% CI 0.36-1.0) with a FPR of 2.4%. The first trimester combined test in twin pregnancies appears to be a good screening method for detecting trisomy 21 in twin pregnancies with high detections rates and very low FPR.