Abstract
Purpose: In this prospective randomized study the effectsof enzymatic treatment of zona pellucida of blastocysts onimplantation and pregnancy rates were evaluated in a groupof patients who had more than five embryos on day 3.
Methods: Forty-six patients with a mean age of 29.8 ± 4.5years and mean duration of infertility of 6.72 ± 0.63 yearshad blastocyst stage transfers, with a mean number of2.9 ± 0.1 embryos replaced per patient. Patients were randomlydivided into two groups. The first group consisted ofpatients (n = 22) who had zona intact blastocyst stagetransfers and the second group consisted of patients (n = 24)who had zona manipulated (enzymatic treatment) blastocyststage transfers. Patient and cycle characteristics were similarin both groups. A commercial cell and serum-free sequentialculture system was used for all embryos.
Results: Overall blastocyst formation rate was 50.3%.Transfer could be done in all patients. The positive β-humanchorionic gonadotropin rate in the zona intact group was50% (11/22) and in the zona-manipulated group was 70.8%(17/24). Clinical pregnancy, ongoing pregnancy, andimplantation rates in zona intact and manipulated groupswere 45.5%, 27.3%, and 19%, and 62.5%, 45.8%, and 24%respectively. Although implantation and pregnancy rates inthe zona-manipulated group were higher, there were nostatistically significant differences in terms of these variablesbetween two groups. No triplet pregnancy was obtained ineither group, and the twin pregnancy rate was 20% (2/10)in the zona intact group and 13.3% (2/15) in thezonamanipulated group.
Conclusions: With further improvements in the embryoculture systems it will become possible in the near future toachieve high implantation rates even with single blastocysttransfers. Enzymatic treatment of the zona pellucida seemsthat it does not alter the pregnancy and implantation rates,but further studies with larger group of patients are neededto clarify the real effect of this zona manipulation onpregnancy outcome.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
REFERENCES
Gardner DK: Mammalian embryo culture in the absence of serum or somatic cell support. Cell Biol Int 1994;18:1163–1179
Gardner DK, Lane M: Culture and selection of viable blastocysts: A feasible proposition for human IVF? Hum Reprod Update 1997;3:367–382
Scholtes MCW, Zeilmaker HG: Blastocyst transfer in day-5 embryo transfer depends primarily on the number of oocytes retrieved and not on age. Fertil Steril 1998;69:78–83
Gardner KD, Vella P, Lane M, et al.: Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers Fertil. Steril. 1998;69:84–88
Jones GM, Trounson AO, Gardner DK, et al.: Evolution of a culture protocol for successful blastocyst development and pregnancy. Hum Reprod 1998;13:169–177
Fong CH, Bongso A, Ng AC, et al.: Blastocyst transfer after enzymatic treatment of the zona pellucida: Improving in vitro fertilization and understanding implantation Hum Reprod 1998;13:2926–2932
de Mouzon J, Lancaster PJ: World Collaborative Report on IVF (preliminary data for 1995). Assist Reprod Genet 1997;14:251S-265S
Gardner DK, Lane M, Spitzer A, et al.: Enhanced rate of cleavage and development for sheep zygotes cultured to the blastocyst stage in vitro in the absence of serum and somatic cells: amino acids, vitamins, and culturing embryos in groups stimulate development. Biol Reprod 1994;50:390–400
Bavister BD: Culture of preimplantation embryos: facts and artifacts. Hum Reprod Update 1995;1:91–148
Buster JE, Bustillo M, Rodi IA, et al.: Biologic and morphologic development of donated human ova by nonsurgical uterine lavage. Am J Obstet Gynecol 1985;153:211–217
Gardner DK, Lane M: Culture of viable human blastocysts in defined sequential serum-free media. Hum Reprod 1998;13:148S-160S
Fong CY, Bongso A, Ng SC, et al.: Ongoing normal pregnancy after transfer of zona-free blastocysts: Implications for embryo transfer Hum Reprod 1997:12;557–560
Gardner DK, Schoolcraft WB, Wagley L, et al.: A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization. Hum Reprod 1998;13:3434–3440
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Isik, A.Z., Vicdan, K., Kaba, A. et al. Comparison of Zona Manipulated and Zona Intact Blastocyst Transfers: A Prospective Randomized Trial. J Assist Reprod Genet 17, 135–139 (2000). https://doi.org/10.1023/A:1009410020580
Issue Date:
DOI: https://doi.org/10.1023/A:1009410020580