Management of Monochorionic Twins: A Comprehensive Review of Major Guidelines

Monochorionic (MC) twin pregnancies are at risk of unique fetal and obstetric complications, which require increased surveillance and specific interventions to minimize the associated neonatal morbidity and mortality.

This review aimed to evaluate and compare the most recently published influential guidelines on the management of monochorionic twin pregnancies.

A comparative review of guidelines from the Royal College of Obstetricians and Gynaecologists (RCOG), the Society of Obstetricians and Gynaecologists of Canada (SOGC), the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (RANZCOG), the International Federation of Gynecology and Obstetrics (FIGO), and the International Society of Ultrasound in Obstetrics and Gynaecology (ISUOG) was carried out.

All the reviewed guidelines recommend the determination of chorionicity and amnionicity in the first trimester, along with the precise labeling of the twins and confirmation of the gestational age based on the crown-rump length of the larger twin or the dates of assisted reproductive techniques. They also encourage the performance of aneuploidy screening during the first trimester, using either a combined nuchal translucency and biochemical markers test or cfDNA. A detailed anatomy scan is recommended, with emphasis on the fetal cardiac assessment. There is agreement on the recommended ultrasonographic surveillance protocol, the diagnostic criteria of TTTS, TAPS, and TRAP, the optimal timing of delivery in case of uncomplicated MC twins, and the need for earlier delivery in case of complications or MCMA twins. All the reviewed medical societies provide similar recommendations regarding the management of pregnancies complicated by TTTS, TAPS, discordant fetal anomaly, and demise of one co-twin. Minor discrepancies were identified regarding the diagnosis and management of sFGR, the routine assessment of cervical length, as well as the first-line aneuploidy screening method.

Multiple pregnancies pose significant maternal, fetal, and obstetric risks compared with singleton pregnancies, with MC twins being at the highest risk of adverse perinatal outcomes, particularly in the absence of increased surveillance or therapeutic interventions. The development and implementation of consistent international evidence-based practice guidelines for the prompt diagnosis and management of MC twin pregnancies and their associated complications may contribute to more favorable outcomes.