Department of Obstetrics and Gynecology, Hirosaki University School of Medicine, Hirosaki, Aomori, Japan
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Abstract |
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Key words: GnRH agonist/implantation/IVF/ovarian stimulation/pregnancy
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Introduction |
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As has been reported previously (Fujii et al., 1997), discontinuation of GnRH agonist on the day of starting HMG impairs follicular development and reduces serum oestradiol concentrations. Based on another report (Sungurtekin and Jansen, 1995
), it was speculated that this inhibitory action of folliculogenesis after stopping GnRH agonist is caused by the decrease in serum gonadotrophin concentrations due to the lack of endogenous GnRH agonist activity. It was postulated that if the cessation of GnRH agonist causes a decrease in circulating serum gonadotrophin concentrations, then the conventional long protocol in which GnRH agonist is stopped before HCG administration may cause an abrupt fall in gonadotrophin concentration at the early luteal phase, and that unexpected effects due to the hormonal changes may follow. Therefore, a comparative prospective and randomized study was conducted to investigate the effect of continuous administration of GnRH agonist during the luteal phase in an ovarian stimulation programme for IVF.
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Materials and methods |
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Procedures for IVF
Ovarian stimulation and IVF was performed as previously described (Fujii et al., 1997). GnRH agonist (Suprecur®; Hoechst, Tokyo, Japan
) 600 µg/day was administered i.n. twice daily from the midluteal phase of the previous cycle, and pure FSH (Fertinorm-P®; Serono, Tokyo, Japan
) administration started on day 7 of the cycle. In both protocols, pure FSH (225 IU) was routinely administered i.m. for 2 days, followed by 150 IU until the mean follicular diameter had reached 18 mm. At 48 h after the final pure FSH administration, 5000 IU of HCG (hCG-Mochida®; Mochida, Tokyo, Japan
) was administered. Oocyte retrieval was performed 3436 h later using ultrasound-guided transvaginal aspiration. For patients treated with conventional IVF, insemination with 105 washed motile spermatozoa/ml (~2x104 spermatozoa per oocyte
) was performed 4 h after oocyte retrieval. For patients treated with ICSI, a spermatozoon was injected into each metaphase II oocyte. Fewer than four cleaved embryos were transferred into the uterine cavity of each patient between 48 and 72 h after oocyte retrieval. The luteal phase was supported by daily oral administration of 10 mg dydrogesterone (Duphaston®; Daiichi-Seiyaku, Tokyo, Japan
) given daily for 14 days, and HCG 2500 IU i.m. on the day of embryo transfer, 7 days after oocyte retrieval. A clinical pregnancy was defined as ultrasound visualization of a gestational sac or histological evidence of trophoblast. In the cL group, GnRH agonist administration was continued until 14 days after oocyte retrieval, when a pregnancy test was performed. In the L group, GnRH agonist was administered until the day before HCG administration. The two protocols differed only when administration of the GnRH agonist was stopped.
Hormone measurements
In both protocols, routine blood sampling for hormonal examination was performed on six occasions: on the initial and final days of pure FSH stimulation; on the day of HCG administration; on the day of oocyte retrieval; on the day of embryo transfer; and 7 days after oocyte retrieval (midluteal phase). Each blood sample was taken before the administration of any medicines. Plasma was assayed for LH, FSH, oestradiol and progesterone using enhanced chemi-iluminescence enzyme immunometric assays (Diagnostic Products Corp., Los Angeles, CA, USA). The lower limit of sensitivity of each bioassay was 0.2 mIU/ml for LH, 0.2 mIU/ml for FSH, 8 pg/ml for oestradiol, and 0.2 ng/ml for progesterone. The intra- and inter-assay coefficients of variation never exceeded 10% and 8% respectively in all cases.
Statistical analysis
Results were analysed using either the unpaired Student's t-test or Fisher's Exact probability test of frequency distribution. A P-value < 0.05 was considered significant.
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Results |
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Discussion |
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However, consequences of profound LH suppression resulting from discontinuation of the agonist administration are still under discussion. When GnRH agonist administration is interrupted, this is followed by an abrupt fall in the serum concentration of
the alpha-subunit of gonadotrophin (Oppenheimer et al., 1992), and a recovery period of hypophyseal synthesis which is usually observed for approximately one week (Winslow et al., 1992
; Sungurtekin and Jansen, 1995
). If GnRH agonist administration was interrupted early in the follicular phase, a profound LH suppression after stopping GnRH agonist lessens the ovarian response to FSH and increases the cancellation rate (Fujii et al., 1997
; Cedrin-Durnerin et al., 2000
). In the case of poor responders, however, the consequences of stopping GnRH agonist may be different. It has been reported (Faber et al., 1998
) that cessation of GnRH agonist at the onset of menses was favourable for poor responders and produced a satisfactory pregnancy rate, whereas others (Dirnfeld et al., 1999
) showed that the cessation brought no further advantage.
The findings of the current study are in line with these previous reports. It was reconfirmed that gonadotrophin responsiveness to daily GnRH agonist administration was preserved, and that interruption of the agonist induced a marked decrease in serum LH concentrations. However, this study is the first to question whether GnRH agonist administration in ovarian stimulation should be stopped before HCG administration. The only differences in serum hormone concentrations between the two groups were observed in gonadotrophins during the luteal phase. Recent reports have shown that profound suppression of LH during ovarian stimulation might increase the risk of early pregnancy loss (Westergaard et al., 2000). However, it is difficult to conjecture that altered luteal function or endometrial receptivity might be the reason why the cL protocol produced a higher implantation rate, as both groups were receiving progesterone and follow-up HCG. Moreover, the current data did not reveal any difference between protocols in serum oestradiol and progesterone concentrations during the luteal phase. These results indicate that our hypothesis, which focused on the altered implantation milieu due to the profound suppression of gonadotrophins after stopping GnRH agonist, were incorrect. Recently, it was reported that administration of GnRH agonist throughout the luteal phase enhanced the fecundity (Raga et al., 1998a
), showing results that are concordant with those of the current study. These authors have also demonstrated the presence of GnRH and its receptor in preimplantation human embryos (Raga et al. 1999a
) and endometrial stromal cells (Raga et al., 1998b
, 1999b
). Therefore, a possible explanation for the promotion of implantation in the cL group might lie in the direct action of GnRH agonist as the regulation in the embryoendometrial interactions and the facilitation of embryonal development.
The routine use of this continuous administration of GnRH agonist has some disadvantages, however. First, prolonged administration will be an economic burden for patients undergoing IVF. Second, the effects of GnRH agonist on embryo implantation in the uterus are not completely clear, although it has been reported that inadvertent exposure of fetuses to GnRH agonist during pregnancy has no specific hazardous effects among newborns (Smitz et al., 1991; Jackson et al., 1992
; Elefant et al., 1995
). The current result also proved the administration of GnRH agonist to be harmless to the early stage of implantation, and also to subsequent fetal development.
In summary, this study has demonstrated that continuation of GnRH agonist administration during the luteal phase might facilitate implantation. Recently, a GnRH antagonist has been developed and a trial of its practical use performed (Craft et al., 1999; Olivennes et al., 2000
). It is certain that a GnRH antagonist will be more valid to prevent a premature LH surge than would a GnRH agonist. However, since unexpected effects of stopping GnRH agonist administration were observed, the pharmacological actions of the antagonist must be closely investigated not only during its administration but also after its cessation.
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Acknowledgements |
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Notes |
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References |
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Chang, S.Y., Lee, C.L., Wang, M.L. et al. (1993) No detrimental effects in delaying initiation of gonadotropin administration after pituitary desensitization with gonadotropin-releasing hormone agonist. Fertil. Steril., 59, 183186.[ISI][Medline]
Craft, I., Gorgy, A., Hill, J. et al. (1999) Will GnRH antagonists provide new hope for patients considered `difficult responders' to GnRH agonist protocols? Hum. Reprod., 14, 29592962.
Cramer, D.W., Powers, D.R., Oskowitz, S.P. et al. (1999) Gonadotropin-releasing hormone agonist use in assisted reproduction cycles: the influence of long and short regimens on pregnancy rates. Fertil. Steril., 72, 8389.[ISI][Medline]
Damario, M.A., Moomjy, M., Tortoriello, D. et al. (1997) Delay of gonadotropin stimulation in patients receiving gonadotropin-releasing hormone agonist (GnRH-a) therapy permits increased clinic efficiency and may enhance in vitro fertilization (IVF) pregnancy rates. Fertil. Steril., 68, 10041010.[ISI][Medline]
Dirnfeld, M., Fruchter, O., Yshai, D. et al. (1999) Cessation of gonadotropin-releasing hormone analogue (GnRH-a) upon down-regulation versus conventional long GnRH-a protocol in poor responders undergoing in vitro fertilization. Fertil. Steril., 72, 406411.[ISI][Medline]
Elefant, E., Biour, B., Blumberg Tick, J. et al. (1995) Administration of a gonadotropin-releasing hormone agonist during pregnancy: follow-up of 28 pregnancies exposed to triptoreline. Fertil. Steril., 63, 11111113.[ISI][Medline]
Faber, B.M., Mayer, J., Cox, B. et al. (1998) Cessation of gonadotropin-releasing hormone agonist therapy combined with high-dose gonadotropin stimulation yields favorable pregnancy results in low responders (see comments). Fertil. Steril., 69, 826830.[ISI][Medline]
Fujii, S., Sagara, M., Kudo, H. et al. (1997) A prospective randomized comparison between long and discontinuous-long protocols of gonadotropin-releasing hormone agonist for in vitro fertilization. Fertil. Steril., 67, 11661168.[ISI][Medline]
Hazout, A., de Ziegler, D., Cornel, C. et al. (1993) Comparison of short 7-day and prolonged treatment with gonadotropin-releasing hormone agonist desensitization for controlled ovarian hyperstimulation. Fertil. Steril., 59, 596600.[ISI][Medline]
Jackson, A.E., Curtis, P., Amso, N. et al. (1992) Exposure to LHRH agonists in early pregnancy following the commencement of mid-luteal buserelin for IVF stimulation. Hum. Reprod., 7, 12221224.[Abstract]
Liu, H.C., Lai, Y.M., Davis, O. et al. (1992) Improved pregnancy outcome with gonadotropin releasing hormone agonist (GnRH-a) stimulation is due to the improvement in oocyte quantity rather than quality. J. Assist. Reprod. Genet., 9, 338344.[ISI][Medline]
Olivennes, F., Belaisch Allart, J., Emperaire, J.C. et al. (2000) Prospective, randomized, controlled study of in vitro fertilization-embryo transfer with a single dose of a luteinizing hormone- releasing hormone (LH-RH) antagonist (cetrorelix) or a depot formula of an LH-RH agonist (triptorelin). Fertil. Steril., 73, 314320.[ISI][Medline]
Oppenheimer, D., Bikkai, H. and Crowley, W. (1992) Effects of chorionic GnRH analogue administration on gonadotrophin and alpha subunit secretion in post-menopausal women. Clin. Endocrinol., 36, 559564.[ISI][Medline]
Pantos, K., Meimeth Damianaki, T., Vaxevanoglou, T. et al. (1994) Prospective study of a modified gonadotropin-releasing hormone agonist long protocol in an in vitro fertilization program. Fertil. Steril., 61, 709713.[ISI][Medline]
Pieters, M.H., Dumoulin, J.C., Engelhart, C.M. et al. (1991) Immaturity and aneuploidy in human oocytes after different stimulation protocols. Fertil. Steril., 56, 306310.[ISI][Medline]
Raga, F., Casañ, E., Ruiz, A., et al. (1998a) Gonadotrophin-releasing hormone agonist administered throughout the luteal phase and early pregnancy increases fecundity in IVF-embryo transfer patients (abstract). 14th Annual meeting of the ESHRE, Gothenburg. Hum. Reprod., 13 (Abstract Bk 1) , 0184.
Raga, F., Casañ, E.M., Kruessel, J.S. et al. (1998b) Quantitative gonadotropin-releasing hormone gene expression and immunohistochemical localization in human endometrium throughout menstrual cycle. Biol. Reprod., 59, 661669.
Raga, F., Casañ, E.M., Kruessel, J.S. et al. (1999a) The role of gonadotropin-releasing hormone in murine preimplantation embryonic development. Endocrinology, 140, 37053712.
Raga, F., Casañ, E.M., Wen, Y. et al. (1999b) Independent regulation of matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and TIMP-3 in human endometrial stromal cells by gonadotropin-releasing hormone: implications in early human implantation. J. Clin. Endocrinol. Metab., 84, 636642.
Ravhon, A., Aurell, R., Lawrie, H. et al. (2000) The significance of delayed suppression using buserelin acetate and recombinant follicle-stimulating hormone in a long protocol in vitro fertilization program. Fertil. Steril., 73, 325329.[ISI][Medline]
Smitz, J., Camus, M., Devroey, P. et al. (1991) The influence of inadvertent intranasal buserelin administration in early pregnancy. Hum. Reprod., 6, 290293.[Abstract]
Smitz, J., Ron El, R. and Tarlatzis, B.C. (1992) The use of gonadotrophin releasing hormone agonists for in vitro fertilization and other assisted procreation techniques: experience from three centres. Hum. Reprod., 7 (Suppl. 1) , 4966.[Abstract]
Sungurtekin, U. and Jansen, R.P.S. (1995) Profound luteinizing hormone suppression after stopping the gonadotropin-releasing hormone-agonist leuprolide acetate. Fertil. Steril., 63, 663665.[ISI][Medline]
Tan, S.L., Kingsland, C., Campbell, S. et al. (1992) The long protocol of administration of gonadotropin-releasing hormone agonist is superior to the short protocol for ovarian stimulation for in vitro fertilization. Fertil. Steril., 57, 810814.[ISI][Medline]
Tasdemir, M., Tasdemir, I., Kodama, H. et al. (1995) Is long-protocol gonadotropin releasing hormone agonist administration superior to the short protocol in ovarian stimulation for in vitro fertilization? Int. J. Fertil. Menopausal Stud., 40, 2528.[Medline]
Westergaard, L.G., Laursen, S.B. and Andersen, C.Y. (2000) Increased risk of early pregnancy loss by profound suppression of luteinizing hormone during ovarian stimulation in normogonadotrophic women undergoing assisted reproduction. Hum. Reprod., 15, 10031008.
Winslow, K.L., Gordon, K., Williams, R.F. and Hodgen, G.D. (1992) Interval required for gonadotropin-releasing hormone-agonist-induced down regulation of the pituitary in cynomolgus monkeys and duration of the refractory state. Fertil. Steril., 58, 12091214.[ISI][Medline]
Submitted on November 16, 2000; accepted on April 30, 2001.