Selection of patients suitable for one-embryo transfer may reduce the rateof multiple births by half without impairment of overall birth rates

The aim of the present study was to identify a subset of patients at high r isk of multiple birth after IVF and hence suitable for one-embryo transfer, which undoubtedly would reduce the multiple birth rate. This retrospective study included 2107 IVF cycles in which two embryos were transferred. Fact ors with possible correlation to multiple birth were studied in a multivari ate analysis, The factors included background data (female age, previous pr egnancies and births, previous IVF cycles, indication for IVF) and IVF cycl e characteristics. The following factors were independently predictive of m ultiple birth: female age expressed a negative correlation while number of goad quality embryos transferred was positively correlated, A subset of pat ients was identified as being at high risk of multiple birth by including a ge, cycle number and presence of tubal infertility in a model derived from a logistic regression analysis. The rate of multiple births can be reduced from 26% to 13% of all births if one-embryo transfer is performed in select ed cases, The total birth rate will decrease from 29% to 25% but may be com pletely restored by performing one additional one-embryo freeze transfer in high risk patients who do not achieve a term pregnancy.