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Prenatal Management of Monoamniotic Twin Pregnancies

Van Mieghem, Tim MD, PhD; De Heus, Roel MD, PhD; Lewi, Liesbeth MD, PhD; Klaritsch, Philipp MD; Kollmann, Martina MD; Baud, David MD, PhD; Vial, Yvan MD; Shah, Prakesh S. MD; Ranzini, Angela C. MD; Mason, Lauren MD; Raio, Luigi MD; Lachat, Regine MD; Barrett, Jon MD, MBBCh; Khorsand, Vesal MD; Windrim, Rory MB; Ryan, Greg MB

doi: 10.1097/AOG.0000000000000409
Contents: Original Research

OBJECTIVE: To evaluate antenatal surveillance strategies and the optimal timing of delivery for monoamniotic twin pregnancies.

METHODS: Obstetric and perinatal outcomes were retrospectively retrieved for 193 monoamniotic twin pregnancies. Fetal and neonatal outcomes were compared between fetuses followed in an inpatient setting and those undergoing intensive outpatient follow-up from 26 to 28 weeks of gestation until planned cesarean delivery between 32 and 35 weeks of gestation. The risk of fetal death was compared with the risk of neonatal complications.

RESULTS: Fetal deaths occurred in 18.1% of fetuses (70/386). Two hundred ninety-five neonates from 153 pregnancies were born alive after 23 weeks of gestation. There were 17 neonatal deaths (5.8%), five of whom had major congenital anomalies. The prospective risk of a nonrespiratory neonatal complication was lower than the prospective risk of fetal death after 32 4/7 weeks of gestation (95% confidence interval 32 0/7–33 4/7). The incidence of death or a nonrespiratory neonatal complication was not significantly different between fetuses managed as outpatients (14/106 [13.2%]) or inpatients (15/142 [10.5%]; P=.55). Our statistical power to detect a difference in outcomes between these groups was low.

CONCLUSIONS: The in utero risk of a monoamniotic twin fetus exceeds the risk of a postnatal nonrespiratory complication at 32 4/7 weeks of gestation. If close fetal surveillance is instituted after 26–28 weeks of gestation and delivery takes place at approximately 33 weeks of gestation, the risk of fetal or neonatal death is low, no matter the surveillance setting.


Close fetal monitoring and elective preterm delivery at approximately 33 weeks of gestation may optimize outcomes in monoamniotic twin pregnancy.

Fetal Medicine Unit, Department of Obstetrics and Gynaecology, and the Neonatal Intensive Care Unit, Department of Paediatrics, Mount Sinai Hospital, and the Department of Obstetrics and Gynaecology, Sunnybrook Health Sciences Centre, University of Toronto, University of Toronto, Toronto, Ontario, Canada; the Department of Woman and Baby, University Medical Centre, Utrecht, The Netherlands; the Fetal Medicine Unit, Department of Obstetrics and Gynaecology, University Hospitals Leuven, Leuven, Belgium; the Department of Obstetrics and Gynaecology, Medical University Graz, Graz, Austria; the Ultrasound and Fetal Medicine Unit, Department of Obstetrics and Gynaecology, Centre Hospitalier Universitaire Vaudois and Swiss Laser Group, Lausanne, Switzerland; Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Saint Peter's University Hospital, New Brunswick, New Jersey; and the Department of Obstetrics and Gynaecology, Inselspital University of Bern and Swiss Laser Group, Bern, Switzerland.

Corresponding author: Greg Ryan, MB, Fetal Medicine Unit, Mount Sinai Hospital, OPG 3-906, 600 University Avenue, ON M5G 1X5, Canada; e-mail:

Presented at the Society for Maternal-Fetal Medicine Annual Meeting, February 3–8, 2014, New Orleans, Louisiana, and the abstract was published (Am J Obstet Gynecol 2014;210:S55).

Financial Disclosure The authors did not report any potential conflicts of interest.

© 2014 by The American College of Obstetricians and Gynecologists.