Hum. Reprod. Advance Access originally published online on July 31, 2007
Human Reproduction 2007 22(9):2576; doi:10.1093/humrep/dem232
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Letters to the Editor |
Reply: Single embryo transfer in preimplantation genetic diagnosis cycles for women <36 years does not reduce delivery rate
Centre for Reproductive Medicine, University Hospital, Dutch-speaking Brussels Free University (Vrije Universiteit Brussel), Laarbeeklaan 101, 1090 Brussels, Belgium
1 Correspondence address. Tel: +56-2-5866130; Fax: +56-2-7531037; E-mail: pdonoso{at}alemana.cl
We greatly appreciate the interest of Drs. Khalaf and El-Toukhy in our study entitled ‘Single embryo transfer in preimplantation genetic diagnosis cycles for women <36 years does not reduce delivery rate’ (Donoso et al., 2007
). The former study represents the first effort to evaluate the impact of single-embryo transfer (SET) in patients undergoing preimplantation genetic diagnosis (PGD) for inherited disorders including only a select group of patients (young age, first treatment cycle) under the framework of the new Belgian legislation. Although we agree on the limitations of the study design, our findings show that performing SET in patients who had more than one embryo available to transfer enabled to avoid multiple pregnancies while achieving a comparable delivery rate to patients who had double-embryo transfer (DET) (37 versus 33.9%, respectively), hence reinforcing the fact that SET does not compromise success rates when applied in these couples. The limited number of patients included in the study is a direct consequence of the strict inclusion criteria used as well as the assessment of delivery rate as the primary outcome measure. We believe that these results require confirmation by further studies including a higher number of couples, however, this is not feasible at our centre since DET cannot be currently performed in these couples.
Our results do not imply that SET should be regarded as a routine practice on patients undergoing PGD, but rather highlight the major advantage of reducing the twin pregnancy rate without comprising the delivery rate in a select group of patients undergoing PGD. We cannot exclude that larger series will show a significant reduction on the delivery rate as shown for non-PGD cycles (Thurin et al., 2004), however, this decrease must be balanced along with the well-known drawbacks of multiple pregnancies. Further research focussed on the improvement of embryo cryopreservation techniques, especially in the case of biopsied embryos, could help broaden the indications of SET in PGD couples.
References
Donoso P, Verpoest W, Papanikolaou EG, Liebaers I, Fatemi HM, Sermón K, Staessen C, Van der Elst J, Devroey P. Single embryo transfer in preimplantation genetic diagnosis cycles for women <36 years does not reduce delivery rate. Hum Reprod (2007) 22:1021–1025.
Thurin A, Hausken J, Hillensjo T, Jablonowska B, Pinborg A, Strandell A, Bergh C. Elective single-embryo transfer versus double-embryo transfer in in-vitro fertilization. N Engl J Med (2004) 351:2392–2402.
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||