PRENATAL DIAGNOSIS: Edited by James F. Smith Jr.Prenatal diagnosis and management of monoamniotic twinsIshii, KeisukeAuthor Information Department of Maternal Fetal Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Osaka, Japan Correspondence to Keisuke Ishii, Department of Maternal Fetal Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, 840 Murodo, Izumi, Osaka, Japan. Tel: +81 725 56 1220; fax: +81 725 57 3207; e-mail: email@example.com Current Opinion in Obstetrics and Gynecology: April 2015 - Volume 27 - Issue 2 - p 159-164 doi: 10.1097/GCO.0000000000000160 Buy Metrics Abstract Purpose of review The purpose of this article is to investigate the perinatal outcomes of monoamniotic twins under current standards of prenatal management involving intensive fetal surveillance. Recent findings The incidence of perinatal mortality in monoamniotic twins has fallen over the last 2 decades. Umbilical cord entanglement has long been considered one of the main causes of poor outcome among monoamniotic twins; however, new evidence shows that it appears to be less important than prematurity and congenital anomalies. If intensive fetal surveillance is provided, the risk of perinatal mortality is acceptably low regardless of setting. In uncomplicated monoamniotic twin pregnancies, delivery at around 33 weeks of gestation might reduce the risk of neonatal adverse events without increasing the risk of perinatal death. Summary Perinatal outcome in monoamniotic twins improved if intensive fetal surveillance was performed under either outpatient or inpatient management. Planned delivery in uncomplicated monoamniotic twin pregnancies can be considered at around 33 weeks of gestation. Copyright © 2015 YEAR Wolters Kluwer Health, Inc. All rights reserved.