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Is blastocyst transfer useful as an alternative treatment for patients with multiple in vitro fertilization failures?
CLINICAL ARTICLES
FERTILITY AND STERILITY威 VOL. 72, NO. 2, AUGUST 1999 Copyright ©1999 American Society for Reproductive Medicine Published by Elsevier Science Inc. Printed on acid-free paper in U.S.A.
Is blastocyst transfer useful as an alternative treatment for patients with multiple in vitro fertilization failures? Jose R. Cruz, M.D., Anil K. Dubey, Ph.D., Jay Patel, M.S., Doug Peak, B.S., Beth Hartog, M.D., and Paul R. Gindoff, M.D. Division of Reproductive Endocrinology, Fertility, and In Vitro Fertilization Program, Department of Obstetrics and Gynecology, The George Washington University Medical Center, Washington, D.C.
Objective: To determine whether blastocyst transfer is of benefit to patients with multiple IVF failures. Design: Retrospective cohort study. Setting: The George Washington University Medical Center. Patient(s): Patients undergoing IVF between October 1, 1997, and November 30, 1998, who had previously undergone three or more unsuccessful IVF cycles. Patients who had at least three embryos at the 8- to 12-cell stage available on day 3 were eligible for the study. Intervention(s): Patients were given the option of day 3 ET (group A) or blastocyst transfer (group B). Main Outcome Measure(s): Blastocyst-formation rate, clinical pregnancy rate (PR) per transfer, and implantation rate per transfer. Result(s): Groups A and B were similar in terms of age, the number of previous failed IVF cycles, fertilization rate, and the number of fertilized oocytes per cycle. The blastocyst-formation rate was 51.0%. Clinical pregnancy and implantation rates per transfer were statistically significantly higher in the blastocysttransfer group. There were no multiple pregnancies after blastocyst transfer. Conclusion: Blastocyst transfer increases implantation rates and PRs in patients with multiple failed IVF cycles, without increasing the risk of multiple pregnancy. (Fertil Steril威 1999;72:218 –20. ©1999 by American Society for Reproductive Medicine.) Key Words: IVF, blastocyst transfer, pregnancy rate, implantation rate
Received December 15, 1998; revised and accepted February 24, 1999. Reprint requests: Anil K. Dubey, Ph.D., Department of Obstetrics and Gynecology, The George Washington University Medical Center, 2150 Pennsylvania Avenue, Washington, D.C. 20037 (FAX: 202-994-5086). 0015-0282/99/$20.00 PII S0015-0282(99)00258-7
218
Recently, the availability of commercially manufactured blastocyst media has enabled cleavage of embryos to the blastocyst stage. Higher pregnancy and implantation rates have been obtained with blastocyst transfer than with transfers of early-cleavage-stage embryos (1). Culturing embryos to the blastocyst stage permits the selection of presumably higher quality embryos, which allows a reduction in the absolute number of embryos for transfer (2– 4). Blastocyst transfer therefore minimizes the risk of multiple gestation. There is an observed decrease in the pregnancy rate (PR) after multiple failed IVF cycles (5). Blastocyst transfer has not been specifically studied in this group of patients. The purpose of this study was to determine whether PRs can be improved in patients with multiple
IVF failures by performing blastocyst transfer rather than transfer on day 3.
MATERIALS AND METHODS We enrolled all patients undergoing IVF between October 1, 1997, and November 30, 1998, who previously underwent three or more unsuccessful IVF cycles and who in the index cycle had at least three embryos available for transfer 3 days after egg retrieval. Patients were not randomized but were given the option (after proper counseling) of having the embryos transferred on day 3 (8- to 12-cell stage) or at the blastocyst stage (day 5 or 6). Group A was composed of patients undergoing day-3 ET (n ⫽ 22), and Group B was composed of patients undergoing blastocyst transfer on day 5 or 6 (n ⫽ 15). The present study was exempted
TABLE 1 Summary of data.
Variable Mean (⫾SD) age in y Mean no. of failed IVF cycles Fertilization rate (%) Mean no. of fertilized oocytes per cycle Mean no. of embryos per transfer Clinical pregnancy rate (%) Implantation rate (%)
Day 3 embryo transfer group (n ⫽ 22)
Day 5 or 6 blastocyst transfer group (n ⫽ 15)
36.9 ⫾ 5.2 4.1 73.3 9.6 5.4 9.1 3.4
35.9 ⫾ 3.6 3.8 70.6 10.1 3.1* 40.0† 11.3†
* P⬍.05 (Student’s t-test). † P⬍.05 (2 test). Fertil Steril ©1999
from Institutional Review Board approval under federal regulation 45 CFR 46, category 4. Ovarian stimulation protocol included the use of a GnRH agonist and the subsequent addition of hMG or FSH. Exogenous gonadotropins were administered daily until the lead follicles averaged between 18 and 20 mm in diameter, as measured by serial vaginal sonography. Human chorionic gonadotropin (10,000 IU) was administered 36.5 hours before transvaginal oocyte retrieval. After retrieval, oocytes were fertilized by either conventional insemination or intracytoplasmic sperm injection. The embryos were cultured in P1 medium (Irvine Scientific, Santa Ana, CA) and 10% synthetic serum substitute (SSS; Irvine Scientific) at 37°C in 5% CO2 up to day 3. On day 3, the embryos of patients in group B were transferred to blastocyst medium (Irvine Scientific) and the embryos of patients in group A were transferred to the uterus. Blastocysts were transferred to the uterus on day 5 or 6. Luteal phase support was provided with progesterone. A serum pregnancy test was performed 17 days after oocyte retrieval. The presence of a gestational sac on ultrasound was considered to indicate clinical pregnancy. Data was analyzed using the 2 and Student’s t-tests where appropriate. P⬍.05 was considered statistically significant.
RESULTS The mean (⫾SD) patient age and number of previous failed IVF cycles in groups A and B were 36.9 ⫾ 5.2 and 35.9 ⫾ 3.6 years and 4.1 and 3.8 cycles, respectively (Table 1). The fertilization rates were 73.3% and 70.6%, and the mean numbers of fertilized oocytes were 9.6 and 10.1, respectively. The mean number of embryos transferred per cycle in group B was significantly lower (P⬍.05) than in group A (3.1 vs. 5.4). FERTILITY & STERILITY威
All patients in group B developed blastocysts for ET, with 51.0% of fertilized eggs reaching the blastocyst stage. The clinical PR per transfer was 9.1% in group A and 40.0% in group B (P⬍.05). The implantation rate per transfer was 3.4% in group A and 11.3% in group B (P⬍.05). There were no multiple pregnancies in group B.
DISCUSSION Patients who underwent multiple failed IVF attempts present a clinical challenge to IVF teams. Studies have shown a decrease in PR after multiple failed IVF cycles (5). We used ET at the blastocyst stage in this particularly difficult group of patients as an alternative to conventional day-3 ET after at least three failed IVF attempts. A recent study by Gardner et al. (6) showed equivalent PRs after day-3 and day-5 ETs, but patients having transfers on day 3 had undergone significantly fewer previous IVF cycles than had those having day-5 transfers. The previous number of IVF cycles was a confounder in this study. In our study, PRs were statistically significantly increased in the group undergoing blastocyst transfer compared with the day-3 ET group (40.0% vs. 9.1%), with both groups having had similar numbers of previous failed IVF cycles. These two groups were also similar in terms of age, fertilization rate, and the number of fertilized oocytes per cycle. Furthermore, the mean ages of patients in the day-3 ET group who conceived and of patients in the blastocyst group who conceived were similar (33 vs. 32.5 years), suggesting that the difference in PR between the groups is not age related. In vivo, the four- to eight-cell human embryo resides in the fallopian tube and enters the uterus only after compaction (2). Because the fallopian tubes and the uterus are different nutritional environments for the embryo, premature transfer to the uterus may compromise the development of cleavagestage embryos (6). Thus, compared with day-3 transfer, blastocyst transfer would be a better physiologic alternative. Blastocyst transfer also permits the selection of presumably higher quality embryos after embryonic genomic activation has occurred. In our study, a statistically significant increase in implantation rate was observed after blastocyst transfer compared with after day-3 ET (11.3% vs. 3.4%). Fewer blastocysts need to be transferred to achieve pregnancy, which reduces the chance of multiple pregnancy. Furthermore, the number of supernumerary embryos for freezing is reduced, which allows an increase of storage capacity at the laboratory and reduces expenses for the patient. A problem with blastocyst transfer is that only approximately half of the fertilized eggs continue to develop to blastocysts (1–3). Some patients therefore might have no embryos available for transfer. Improvement of culture me219
dia may help prevent this outcome. However, failure of blastocyst formation in vitro may also indicate lower oocyte, sperm, or embryonic quality (4). In conclusion, blastocyst transfer appears to be a successful and improved alternative for patients with multiple failed attempts at IVF. With blastocyst transfer, there is a decreased risk of multiple pregnancy, because fewer embryos are transferred. Blastocyst transfer can also aid in evaluating embryo quality. Although statistically significant differences between blastocyst transfer and convential day-3 ET were noted in our study, the number of patients was small, affecting the power of the study. A larger sample is needed to further evaluate these findings.
220
Cruz et al.
Blastocyst transfer for failed-IVF patients
References 1. Alves da Motta EL, Alegretti JR, Baracat EC, Olive D, Serafini PC. High implantation and pregnancy rates with transfer of human blastocysts developed in preimplantation stage one and blastocyst media. Fertil Steril 1998;70:659 – 63. 2. Gardner DK, Vella P, Lane M, Wagley L, Schlenker T, Schoolcraft WB. Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers. Fertil Steril 1998; 69:84 – 8. 3. Scholtes MCW, Zeilmaker GH. A prospective, randomized study of embryo transfer results after 3 or 5 days of embryo culture in in vitro fertilization. Fertil Steril 1996;65:1245– 8. 4. Jones GM, Trounson AO, Lolatgis N, Wood C. Factors affecting the success of human blastocyst development and pregnancy following in vitro fertilization and embryo transfer. Fertil Steril 1998;70:1022–9. 5. Hershlag A, Kaplan EH, Loy RA, DeCherney AH, Lavy G. Heterogeneity in patient populations explains differences in in vitro fertilization programs. Fertil Steril 1991;56:913–7. 6. Gardner DK, Schoolcraft WB, Wagley L, Schlenker T, Stevens J, Hesla J. A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization. Hum Reprod 1998;13:3434 – 40.
Vol. 72, No. 2, August 1999
FERTILITY AND STERILITY威 VOL. 72, NO. 2, AUGUST 1999 Copyright ©1999 American Society for Reproductive Medicine Published by Elsevier Science Inc. Printed on acid-free paper in U.S.A.
Is blastocyst transfer useful as an alternative treatment for patients with multiple in vitro fertilization failures? Jose R. Cruz, M.D., Anil K. Dubey, Ph.D., Jay Patel, M.S., Doug Peak, B.S., Beth Hartog, M.D., and Paul R. Gindoff, M.D. Division of Reproductive Endocrinology, Fertility, and In Vitro Fertilization Program, Department of Obstetrics and Gynecology, The George Washington University Medical Center, Washington, D.C.
Objective: To determine whether blastocyst transfer is of benefit to patients with multiple IVF failures. Design: Retrospective cohort study. Setting: The George Washington University Medical Center. Patient(s): Patients undergoing IVF between October 1, 1997, and November 30, 1998, who had previously undergone three or more unsuccessful IVF cycles. Patients who had at least three embryos at the 8- to 12-cell stage available on day 3 were eligible for the study. Intervention(s): Patients were given the option of day 3 ET (group A) or blastocyst transfer (group B). Main Outcome Measure(s): Blastocyst-formation rate, clinical pregnancy rate (PR) per transfer, and implantation rate per transfer. Result(s): Groups A and B were similar in terms of age, the number of previous failed IVF cycles, fertilization rate, and the number of fertilized oocytes per cycle. The blastocyst-formation rate was 51.0%. Clinical pregnancy and implantation rates per transfer were statistically significantly higher in the blastocysttransfer group. There were no multiple pregnancies after blastocyst transfer. Conclusion: Blastocyst transfer increases implantation rates and PRs in patients with multiple failed IVF cycles, without increasing the risk of multiple pregnancy. (Fertil Steril威 1999;72:218 –20. ©1999 by American Society for Reproductive Medicine.) Key Words: IVF, blastocyst transfer, pregnancy rate, implantation rate
Received December 15, 1998; revised and accepted February 24, 1999. Reprint requests: Anil K. Dubey, Ph.D., Department of Obstetrics and Gynecology, The George Washington University Medical Center, 2150 Pennsylvania Avenue, Washington, D.C. 20037 (FAX: 202-994-5086). 0015-0282/99/$20.00 PII S0015-0282(99)00258-7
218
Recently, the availability of commercially manufactured blastocyst media has enabled cleavage of embryos to the blastocyst stage. Higher pregnancy and implantation rates have been obtained with blastocyst transfer than with transfers of early-cleavage-stage embryos (1). Culturing embryos to the blastocyst stage permits the selection of presumably higher quality embryos, which allows a reduction in the absolute number of embryos for transfer (2– 4). Blastocyst transfer therefore minimizes the risk of multiple gestation. There is an observed decrease in the pregnancy rate (PR) after multiple failed IVF cycles (5). Blastocyst transfer has not been specifically studied in this group of patients. The purpose of this study was to determine whether PRs can be improved in patients with multiple
IVF failures by performing blastocyst transfer rather than transfer on day 3.
MATERIALS AND METHODS We enrolled all patients undergoing IVF between October 1, 1997, and November 30, 1998, who previously underwent three or more unsuccessful IVF cycles and who in the index cycle had at least three embryos available for transfer 3 days after egg retrieval. Patients were not randomized but were given the option (after proper counseling) of having the embryos transferred on day 3 (8- to 12-cell stage) or at the blastocyst stage (day 5 or 6). Group A was composed of patients undergoing day-3 ET (n ⫽ 22), and Group B was composed of patients undergoing blastocyst transfer on day 5 or 6 (n ⫽ 15). The present study was exempted
TABLE 1 Summary of data.
Variable Mean (⫾SD) age in y Mean no. of failed IVF cycles Fertilization rate (%) Mean no. of fertilized oocytes per cycle Mean no. of embryos per transfer Clinical pregnancy rate (%) Implantation rate (%)
Day 3 embryo transfer group (n ⫽ 22)
Day 5 or 6 blastocyst transfer group (n ⫽ 15)
36.9 ⫾ 5.2 4.1 73.3 9.6 5.4 9.1 3.4
35.9 ⫾ 3.6 3.8 70.6 10.1 3.1* 40.0† 11.3†
* P⬍.05 (Student’s t-test). † P⬍.05 (2 test). Fertil Steril ©1999
from Institutional Review Board approval under federal regulation 45 CFR 46, category 4. Ovarian stimulation protocol included the use of a GnRH agonist and the subsequent addition of hMG or FSH. Exogenous gonadotropins were administered daily until the lead follicles averaged between 18 and 20 mm in diameter, as measured by serial vaginal sonography. Human chorionic gonadotropin (10,000 IU) was administered 36.5 hours before transvaginal oocyte retrieval. After retrieval, oocytes were fertilized by either conventional insemination or intracytoplasmic sperm injection. The embryos were cultured in P1 medium (Irvine Scientific, Santa Ana, CA) and 10% synthetic serum substitute (SSS; Irvine Scientific) at 37°C in 5% CO2 up to day 3. On day 3, the embryos of patients in group B were transferred to blastocyst medium (Irvine Scientific) and the embryos of patients in group A were transferred to the uterus. Blastocysts were transferred to the uterus on day 5 or 6. Luteal phase support was provided with progesterone. A serum pregnancy test was performed 17 days after oocyte retrieval. The presence of a gestational sac on ultrasound was considered to indicate clinical pregnancy. Data was analyzed using the 2 and Student’s t-tests where appropriate. P⬍.05 was considered statistically significant.
RESULTS The mean (⫾SD) patient age and number of previous failed IVF cycles in groups A and B were 36.9 ⫾ 5.2 and 35.9 ⫾ 3.6 years and 4.1 and 3.8 cycles, respectively (Table 1). The fertilization rates were 73.3% and 70.6%, and the mean numbers of fertilized oocytes were 9.6 and 10.1, respectively. The mean number of embryos transferred per cycle in group B was significantly lower (P⬍.05) than in group A (3.1 vs. 5.4). FERTILITY & STERILITY威
All patients in group B developed blastocysts for ET, with 51.0% of fertilized eggs reaching the blastocyst stage. The clinical PR per transfer was 9.1% in group A and 40.0% in group B (P⬍.05). The implantation rate per transfer was 3.4% in group A and 11.3% in group B (P⬍.05). There were no multiple pregnancies in group B.
DISCUSSION Patients who underwent multiple failed IVF attempts present a clinical challenge to IVF teams. Studies have shown a decrease in PR after multiple failed IVF cycles (5). We used ET at the blastocyst stage in this particularly difficult group of patients as an alternative to conventional day-3 ET after at least three failed IVF attempts. A recent study by Gardner et al. (6) showed equivalent PRs after day-3 and day-5 ETs, but patients having transfers on day 3 had undergone significantly fewer previous IVF cycles than had those having day-5 transfers. The previous number of IVF cycles was a confounder in this study. In our study, PRs were statistically significantly increased in the group undergoing blastocyst transfer compared with the day-3 ET group (40.0% vs. 9.1%), with both groups having had similar numbers of previous failed IVF cycles. These two groups were also similar in terms of age, fertilization rate, and the number of fertilized oocytes per cycle. Furthermore, the mean ages of patients in the day-3 ET group who conceived and of patients in the blastocyst group who conceived were similar (33 vs. 32.5 years), suggesting that the difference in PR between the groups is not age related. In vivo, the four- to eight-cell human embryo resides in the fallopian tube and enters the uterus only after compaction (2). Because the fallopian tubes and the uterus are different nutritional environments for the embryo, premature transfer to the uterus may compromise the development of cleavagestage embryos (6). Thus, compared with day-3 transfer, blastocyst transfer would be a better physiologic alternative. Blastocyst transfer also permits the selection of presumably higher quality embryos after embryonic genomic activation has occurred. In our study, a statistically significant increase in implantation rate was observed after blastocyst transfer compared with after day-3 ET (11.3% vs. 3.4%). Fewer blastocysts need to be transferred to achieve pregnancy, which reduces the chance of multiple pregnancy. Furthermore, the number of supernumerary embryos for freezing is reduced, which allows an increase of storage capacity at the laboratory and reduces expenses for the patient. A problem with blastocyst transfer is that only approximately half of the fertilized eggs continue to develop to blastocysts (1–3). Some patients therefore might have no embryos available for transfer. Improvement of culture me219
dia may help prevent this outcome. However, failure of blastocyst formation in vitro may also indicate lower oocyte, sperm, or embryonic quality (4). In conclusion, blastocyst transfer appears to be a successful and improved alternative for patients with multiple failed attempts at IVF. With blastocyst transfer, there is a decreased risk of multiple pregnancy, because fewer embryos are transferred. Blastocyst transfer can also aid in evaluating embryo quality. Although statistically significant differences between blastocyst transfer and convential day-3 ET were noted in our study, the number of patients was small, affecting the power of the study. A larger sample is needed to further evaluate these findings.
220
Cruz et al.
Blastocyst transfer for failed-IVF patients
References 1. Alves da Motta EL, Alegretti JR, Baracat EC, Olive D, Serafini PC. High implantation and pregnancy rates with transfer of human blastocysts developed in preimplantation stage one and blastocyst media. Fertil Steril 1998;70:659 – 63. 2. Gardner DK, Vella P, Lane M, Wagley L, Schlenker T, Schoolcraft WB. Culture and transfer of human blastocysts increases implantation rates and reduces the need for multiple embryo transfers. Fertil Steril 1998; 69:84 – 8. 3. Scholtes MCW, Zeilmaker GH. A prospective, randomized study of embryo transfer results after 3 or 5 days of embryo culture in in vitro fertilization. Fertil Steril 1996;65:1245– 8. 4. Jones GM, Trounson AO, Lolatgis N, Wood C. Factors affecting the success of human blastocyst development and pregnancy following in vitro fertilization and embryo transfer. Fertil Steril 1998;70:1022–9. 5. Hershlag A, Kaplan EH, Loy RA, DeCherney AH, Lavy G. Heterogeneity in patient populations explains differences in in vitro fertilization programs. Fertil Steril 1991;56:913–7. 6. Gardner DK, Schoolcraft WB, Wagley L, Schlenker T, Stevens J, Hesla J. A prospective randomized trial of blastocyst culture and transfer in in-vitro fertilization. Hum Reprod 1998;13:3434 – 40.
Vol. 72, No. 2, August 1999