Polyhydramnios Affecting a Recipient-like Twin: Risk of Progression to Twin-Twin Transfusion Syndrome and Outcomes.

Objective: The significance of polyhydramnios of one twin in the absence of oligohydramnios of the cotwin in monochorionic diamniotic (MCDA) twin pregnancies (polyhydramnios affecting a recipient-like twin [PART]) is unknown. Our aim is to assess the risk of progression to twin-twin transfusion syndrome (TTTS) with PART, progression to ≥ stage II TTTS, and neonatal survival.

Study Design: This study was a retrospective cohort study of MCDA twin pregnancies with PART evaluated at a referral center from 2008 to 2015.

Results: Sixty-four MCDA twin pregnancies with PART were identified. Fifteen (23.4%) progressed to TTTS, including 10 (15.6%) who progressed to ≥ stage II TTTS. Three pregnancies were terminated and one underwent selective reduction by radiofrequency ablation. Overall survival was 113 out of 128 (88.3%). Of those who remained stable, 91.8% ( = 45) had survival of both neonates. In multivariate analysis, the presence of arterioarterial (A-A) anastomosis by in utero Doppler ultrasound was associated with decreased risk of progression to TTTS (odds ratio: 0.12,  = 0.03, 95% confidence interval: 0.02-0.78).

Conclusion: Most MCDA twin pregnancies with PART do not progress to TTTS and have a favorable prognosis. Progression rates are higher than observed in uncomplicated MCDA twins; however, so close surveillance is warranted. The presence of an A-A anastomosis appears to confer decreased risk of progression to TTTS.