Stage I Twin-Twin Transfusion Syndrome: Outcomes of Expectant Management and Prognostic Features.

OBJECTIVE:  This article describes the natural history of stage I twin-twin transfusion syndrome (TTTS) including risk of progression to higher stage TTTS and pregnancy outcomes, and to identify risk factors for progression.

STUDY DESIGN:  Retrospective cohort study of monochorionic diamniotic (MCDA) twin pregnancies from 2006 to 2016 with expectantly managed Quintero stage I TTTS.

RESULTS:  A total of 30 MCDA twin pregnancies with expectantly managed stage I TTTS were identified. Of these, eight (26.7%) progressed to higher stage TTTS. Median gestational age (GA) at diagnosis for those that progressed was 18.9 ± 2.9 weeks versus 21.4 ± 3.4 weeks in those that remained stable ( p  = 0.06). Presence of an arterioarterial (A-A) anastomosis was assessed for 20/30 patients, and eight A-A were identified. Of those, 7/8 (87.5%) remained stable. In the complete cohort, a tiny or transiently visible bladder was noted in seven donor twins. Of these, 4/7 (57.1%) progressed. Excluding one termination, 47/58 (81.0%) fetuses survived.

CONCLUSION:  With expectant management of stage I TTTS, nearly three-fourths of pregnancies remain stable and most have survival of ≥ 1 twin. A-A anastomoses were not associated with progression to higher stage TTTS, whereas earlier GA at diagnosis or a small or intermittently visible donor bladder may herald greater risk of progression.