An update on antenatal screening for Down's syndrome and specific implications for assisted reproduction pregnancies.

Since the introduction of antenatal serum screening for Down's syndrome (DS) more than two decades ago, several screening approaches have been utilized in routine clinical practice. The current DS screening strategies involve mid-trimester serum biochemistry tests, first trimester tests combining sonographic markers and serum biochemistry and integration of first and second trimester markers. In this review, we evaluate the performance of DS screening strategies according to the Serum, Urine and Ultrasound Screening Study (SURUSS), the First and Second Trimester Evaluation of Risks (FASTER) Trial and the Serum Biochemistry and Fetal Nuchal Translucency Screening (BUN) Study. We also evaluate the performance of first trimester screening in studies and meta-analyses by other groups. Specific issues related to assisted reproduction technology (ART) pregnancies are also addressed in this review.