Vanishing twin syndrome

Abstract

The vanishing twin syndrome (VTS) is defined as a spontaneous demise of one twin or one gestational twin sac in a multiple pregnancy in the first trimester. The incidence of VTS is increased in assisted reproduction techniques (ART) pregnancies, fundamentally due to the increased twin pregnancy rate rather than ART per se. Vanishing twin syndrome seems to be associated with adverse outcomes affecting the remaining survivor both in spontaneously conceived pregnancies and ART pregnancies. Vanishing twin syndrome can influence the measurement of invasive and noninvasive screening techniques. Conclusion: To date, the evidence of the short and long-term effects of VTS on the surviving fetus is discordant. We can reduce its incidence by correcting some predisposing factors. Early detection of VTS and meticulous ultrasound monitoring of the alive twin for the entire pregnancy is mandatory to identify possible adverse obstetric outcomes.