Monoamniotic twins: diagnosis and management

Abstract

Monoamniotic twins, although uncommon, are associated with high antenatal and perinatal morbidity and mortality. The associated complications include cord entanglement, congenital anomalies, twin-twin transfusion syndrome, intrauterine growth retardation and preterm delivery. A thorough literature search using Medline and OVID was performed to look at the current diagnostic criteria for monoamniotic twins and the subsequent management. Specific criteria are employed during ultrasonography for making the diagnosis. Different opinions in the literature exist regarding the proper antepartum monitoring of monoamniotic twins, the optimal timing and the mode of delivery. Generally, it is agreed that there should be regular antepartum fetal heart trace monitoring and serial sonograms with umbilical artery Doppler flow study. Most studies advocate delivery at 32 weeks to reduce the risk of intrauterine deaths related to cord entanglement. Cesarean section is the preferred mode of delivery even though cases of successful vaginal delivery have been reported.

Vaginal Delivery of Twins

“…In addition to cord entanglement and accidents, congenital anomalies, growth restriction, single intrauterine fetal death along with multicystic leukomalacia in the surviving co-twin, and twin-twin transfusion syndrome are other factors contributing to the high perinatal mortality rate. 52,53,59 Ultrasound is the most common means of diagnosis when a dividing membrane is not seen with a twin intrauterine gestation. Most agree that close monitoring of these twins should begin at viability.…”

Perinatal outcome and clinical features of monochorionic monoamniotic twin gestation

“…4 In particular, umbilical cord entanglement has been considered to account for 50-65% of perinatal mortality in MM twins. 5,6 Despite the foregoing, several recent studies of MM twins report a fetal loss rate after 20 weeks of gestation of 13% to 15% 7,8 and a perinatal mortality rate of 17% or less. 7 These studies also report a lower prevalence of cord entanglement for perinatal loss in MM twin gestations.…”

Case Series of Monoamniotic and Pseudomonoamniotic Twin Gestations

“…The most common cause of perinatal mortality in monoamniotic twins has been reported to be cord entanglement [1, 2]. Cord entanglement has been reported in up to 70% of monoamniotic twins with 50% or more of deaths attributed to this complication [3]. Recently, some cases of disruption of the dividing membrane in monochorionic diamniotic twin gestation as pseudomonoamniotic twin gestation [4–13].…”