Monochorionic Twin Pregnancy Complicated by Right Ventricular Outflow Tract Obstruction (RVOTO) of one Fetus without Proof of a Twin-Twin Transfusion Syndrome

Introduction

Monochorionic twin pregnancies are at high risk for the development of severe complications such as twin-twin transfusion syndrome (TTTS) or selective intrauterine growth restriction (sIUGR). In TTTS the development of cardiovascular failure due to acquired right ventricular outflow tract obstruction (RVOTO) is one major problem which may result in fetal demise (Lougheed J, Sinclair BG, Fung Kee Fung K et al. Journal of the American College of Cardiology 2001; 38: 1533 – 1538). The formerly normal heart of the recipient may develop cardiac hypertrophy and tricuspid regurgitation followed by RVOTO due to an increased preload. In sIUGR this mechanism has not been evaluated clearly, so far. We present a case of monochorionic twins at 26 + 0 weeks of gestation where the larger fetus developed an RVOTO with severe cardiac insufficiency without characteristics of TTTS. Fetal echocardiography, Doppler parameters and outcome are described.