Single embryo transfer in preimplantation genetic diagnosis cycles for women <36 years does not reduce delivery rate

BACKGROUND: The Belgian legislation imposes single embryo transfer (SET) on women of <36 years in their first treatment cycle to avoid multiple pregnancies. The aim of this study is to assess the impact of this legislation on the outcome of preimplantation genetic diagnosis (PGD) for inherited diseases in young women undergoing SET. METHODS: A retrospective analysis of PGD cycles for monogenic disorders and translocations in women <36 years on their first treatment cycle. Two groups of patients were defined according to the implementation of the Belgian legislation: (i) double embryo transfer (DET), January 2001-June 2003 (ii) SET, July 2003-June 2005. The primary and secondary outcome measures were delivery per embryo transfer and multiple pregnancy rates, respectively. A subgroup analysis for monogenic disorders and translocations was performed. RESULTS: 62 cycles were included in the DET group and 73 cycles in the SET group. The mean age, number of cumulus-oocyte complexes, number of fertilized oocytes, number of biopsied and cryopreserved embryos were comparable between both groups. There was no significant difference in the delivery rates between the DET and the SET groups (33.9% versus 27.4%, respectively). Multiple pregnancies were avoided when SET was performed. When monogenic disorders and chromosomal translocations were separately evaluated, no significant difference in the delivery rate after SET was observed. CONCLUSIONS: The implementation of a SET policy in young women undergoing PGD for monogenic disorders and translocations enables a significant reduction of multiple pregnancies without significantly affecting the delivery rate.