How many embryos should be transferred? A validated score to predict ongoing implantation rate.
OBJECTIVE
To developed a prognostic score to predict ongoing implantation rate according to clinical and biological parameters and to choose the number of embryos to be transferred in patients undergoing IVF/ICSI.


METHODS
The transfer score was established using multivariate analysis of biological and clinical parameters in 3211 fresh embryo transfers in a retrospective study. Then we validated the score in 694 fresh embryo transfers in a prospective study. We assessed ongoing implantation rates, ongoing pregnancy rates, multiple pregnancy rates and live birth rate.


RESULTS
Among the different variables tested, 4 were identified that influenced the implantation rate: female age, the ratio of retrieved oocytes/mean daily dose of injected FSH, attempt rank and the morphology of the embryo cohort. Prospective application of this score resulted in significantly lower number of transferred embryos (1.8 vs 2.0 P<0.001) and lower twins rates (9.7% vs 17.3%, P<0.001) without decreasing live birth rates.


CONCLUSIONS
Although the risks of multiple pregnancies should not be ignored, it appears excessive to impose the limit of 2 embryos for transfer particularly in situations with a poor prognosis. We sought to provide a personalized prognosis by using clinical and embryo data in order to choose the number of embryo(s) for transfer with a moderate multiple pregnancy rate of less than 11%.
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France; EA 3694 Human Fertility Research Group, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France. Electronic address: gatimel.n@chu-toulouse.fr.
Nicolas
N
Gatimel
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Melissa
M
Ladj
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Carole
C
Teston
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Florence
F
Lesourd
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Carole
C
Fajau
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Clémentine
C
Cohade
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France; EA 3694 Human Fertility Research Group, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Jean
J
Parinaud
Service de Médecine de la Reproduction, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France; EA 3694 Human Fertility Research Group, Hôpital Paule de Viguier, CHU Toulouse, 330 Avenue de Grande Bretagne, 31059 Toulouse, France.
Roger D
RD
Léandri
D000328:Adult; D000367:Age Factors; D010064:Embryo Implantation; D004624:Embryo Transfer / Q000379:methods / Q000592:standards*; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data*; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage; D006801:Humans; D054315:Oocyte Retrieval / Q000592:standards*; D011247:Pregnancy; D018873:Pregnancy Rate; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors
D005640:Follicle Stimulating Hormone
Embryo transfer; Implantation; Multiple pregnancy; Number of embryos; Score