Review: PDF OnlyTwin Anemia Polycythemia Sequence Knowledge and Insights After 15 Years of ResearchTollenaar, Lisanne S.A.1,*; Lopriore, Enrico2; Oepkes, Dick1; Haak, Monique C.1; Klumper, Frans J.C.M.1; Middeldorp, Johanna M.1; Klink, Jeanine M.M. Van2; Slaghekke, Femke1Editor(s): Pan, Yang Author Information 1Department of Obstetrics, Division of Fetal therapy, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands 2Department of Pediatrics, Division of Neonatology, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands. Corresponding author: Lisanne S.A. Tollenaar, Department of Obstetrics, Division of Fetal therapy, Leiden University Medical Center, Leiden 2333 ZA, The Netherlands. E-mail: [email protected] Received April 17, 2020 This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal. http://creativecommons.org/licenses/by-nc-nd/4.0 Maternal-Fetal Medicine: September 10, 2020 - Volume Latest Articles - Issue - doi: 10.1097/FM9.0000000000000065 Open PAP Metrics Abstract Twin anemia polycythemia sequence (TAPS) is a chronic form of unbalanced feto-fetal transfusion through minuscule placental anastomoses in monochorionic twin pregnancies, leading to anemia in the donor twin and polycythemia in the recipient twin. TAPS can occur spontaneously in up to 5% of monochorionic twins or can arise in 2%–16% of cases after incomplete laser surgery for twin-twin transfusion syndrome. TAPS can develop across the entire second and third trimester. Antenatal diagnosis for TAPS is reached via Doppler measurement of the fetal middle cerebral artery – peak systolic velocity, showing an increased velocity in the donor, combined with a decreased velocity in the recipient. Treatment options for TAPS include expectant management, preterm delivery, intrauterine blood transfusion with or without a partial exchange transfusion, fetoscopic laser surgery and selective feticide. The best treatment option is unclear and is currently being investigated in an international multicenter randomized trial (the TAPS trial). Spontaneous fetal demise occurs in 5%–11% of TAPS twins, more often in donors (8%–18%) than in recipients (2%–5%). Severe long-term neurodevelopmental impairment is seen in 9% of TAPS twins, with donors having an increased risk for cognitive impairment and hearing problems (15%). © 2020 by Lippincott Williams & Wilkins, Inc.