INTRODUCTION

It has always been silently accepted that a high proportion of iatrogenic twins and high-order multiple pregnancies (HOMPs) was the price to be paid for a reasonable success rate of a treatment that is physically and emotionally demanding and, in many cases, expensive (Rizk et al. 1989). Even though many twins are delivered healthy and advances in neonatal medicine have decreased mortality and morbidity of premature babies from multiple pregnancies, there remains an important increase in the absolute numbers of (severe) pathologies. Tan et al. also pointed to the possible increase in average costs for multiple pregnancies, deliveries, and neonatal care (Rizk et al. 1991; Tan et al. 1992; Hidlebaugh et al. 1997; Wølner-Hanssen and Rydhstroem 1998; De Sutter et al. 2002; Ericson et al. 2002; Garceau et al. 2002; Ellison and Hall 2003); severe stress experienced by parents of multiples (Ostfeld et al. 2000; Glazebrook et al. 2004); and the lifelong support needed for mildly or severely disabled children.

MP causes several well-documented pathologies, extensively reviewed elsewhere (Dhont et al. 1997, 1999; Pons et al. 1998a,b; Senat et al. 1998; Bergh et al. 1999; Koudstaal et al. 2000a,b; Wennerholm and Bergh 2000, 2004a,b; Rydhstroem and Heraib 2001; Klemetti et al. 2002; Lynch et al. 2002; Strömberg et al. 2002; Wang et al. 2002; Helmerhorst et al. 2004), comprising both maternal and fetal/neonatal risks and complications.