“…Although it may seem that the only difference between IVF and natural conception is the conception itself, there are a number of reasons why having a child by IVF may result in a rather different experience for parents. One very important difference is the higher incidence of multiple births, preterm births and low birth weight infants following IVF (e.g., Beral, Doyle, Tan, Mason, & Campbell, 1990;Olivennes et al, 2002;Rufat, Olivennes, de Mouzon, Dehan, & Frydman, 1994;SART Registry, 1999;Tan et al, 1992;Tanbo, Dale, Lunde, Moe, & Abyholm, 1995;Vayena & Rowe, 2002;Wang et al, 1994;Westergard, Johansen, Erb, & Andersen, 1999). Whereas only 1% of natural births involve twins, triplets or more, this is true of more than one-quarter of births resulting from IVF.…”