Is twin pregnancy necessarily an adverse outcome of assisted reproductive technologies?

It has recently been suggested that the measure of success of assisted reproductive technologies (ART) should be the birth of a singleton baby, whereas a twin pregnancy should be considered as a complication. Although the maternal and neonatal complications in twin pregnancies are significantly higher than those in singleton pregnancies, the classification of a twin pregnancy as a complication of ART is in our opinion debatable. Most twin pregnancies result in the birth of two healthy babies, with little or no complication for the mother, and only few twin pregnancies results in serious morbidity of the mother and of one or both of the children. The crux of our arguments is that one should consider those cases as poor outcomes and not a twin pregnancy per se.